# News this Week

Science  18 May 2001:
Vol. 292, Issue 5520, pp. 1274
1. INTELLECTUAL PROPERTY

# Alzheimer's Researcher in Japan Accused of Economic Espionage

1. Eliot Marshall,
2. Dennis Normile

WASHINGTON, D.C., AND TOKYO—Scientists who study Alzheimer's disease were shocked last week to learn that the U.S. Justice Department has indicted one of their colleagues, Takashi Okamoto, for conspiring “to benefit a foreign government” and “steal” trade secrets. Okamoto's peers, who describe him as brilliant but eccentric, are puzzled by the severity of the charges involving material that appears to have no commercial value.

The Japanese-born Okamoto is accused of stealing cell lines and DNA samples from a laboratory at the Cleveland Clinic Foundation in Ohio, where he worked from 1997 to 1999, and taking them to a new job at the Institute of Physical and Chemical Research (RIKEN) near Tokyo. The indictment says that his goal was “to ensure that RIKEN acquired a competitive advantage over” U.S. scientists studying Alzheimer's disease. The charges, based on the Economic Espionage Act of 1996, depend in part on RIKEN's status as a government entity. The economic espionage charge carries a maximum penalty of 15 years in prison.

Academic researchers often take reagents with them when they move to another lab. But Okamoto violated community norms, according to the indictment, by removing materials without permission, substituting fake samples, and abruptly quitting his job at the clinic's Lerner Research Institute (LRI). If Okamoto had asked, says institute director George Stark, he would have received permission to take samples, because “that's standard procedure.” Stark says Okamoto's research at the institute had produced no patentable discoveries.

At LRI, Okamoto studied cell signaling and cell death in connection with Alzheimer's disease. The federal indictment, issued 8 May by a grand jury in Cleveland, charges that he, with the help of two friends, removed reagents from LRI and transported them to Japan. A third friend, Hiroaki Serizawa, a researcher at the University of Kansas Medical Center in Kansas City, denied involvement but was arrested as a co-conspirator. Okamoto remains free in Japan.

The problems at LRI came to light, according to Stark, after postdocs in Okamoto's lab complained that “reagents were missing or didn't work.” The institute conducted its own investigation and called in local police, who “decided the FBI needed to be involved,” Stark says. He adds that “it was important that we report an infraction of the law appropriately, regardless of the consequences.” Stark says Okamoto was “quite productive before and after” his arrival at LRI, although Stark adds that work in his lab “came to a complete stop” after the reagents disappeared.

According to the indictment, Okamoto and a “Dr. A” removed some cell lines and DNA samples from LRI and destroyed others on the night of 8 July 1999. Okamoto allegedly stored four boxes of reagents at the home of a “Dr. B,” where Okamoto was living temporarily. The indictment says Okamoto shipped the materials to Serizawa in Kansas City, abruptly resigned his post, and began work at RIKEN. He returned to Kansas City on 16 August 1999, according to the indictment, to retrieve the reagents and take them to RIKEN.

Masao Ito, president of RIKEN's Brain Science Institute, says he was astonished when he heard the charges against Okamoto, a research group leader there. “We had never received any contact from [LRI], the FBI, or the U.S. Department of Justice,” he says. According to Ito, Okamoto has followed a completely different line of research since moving to RIKEN, involving the role of cholesterol metabolism in the production of the plaque that is one of the neuropathological hallmarks of Alzheimer's disease. “His current research is just beginning to go well,” Ito says.

Okamoto, who went on leave after the indictment was handed up, could not be reached for comment. His attorney, Brent Gurney of the Wilmer, Cutler, & Pickering law firm in Washington, D.C., says Okamoto did not transport “any genetic material” to RIKEN and is innocent. Gurney says that repeated requests to address the government's concerns were spurned. RIKEN officials say Okamoto had informed his boss in fall 1999 of the investigation. “But we had thought it was strictly a private matter,” Ito says.

Okamoto seems unlikely to face trial unless he is extradited to the United States. Serizawa was arrested in Kansas City on 10 May and is expected to appear shortly in federal court in Cleveland. His attorney, Jean Paul Bradshaw of the Lathrop and Gage law firm in Kansas City, says his client “absolutely denies the charges” and is “very surprised, because we cooperated with the investigation and hadn't heard from the government for a year.”

Okamoto's motivation and the fate of the samples remain a mystery. Kiyoshi Kurokawa, dean of Tokai University School of Medicine in Hiratsuka and one of his former professors, says Okamoto may not have been “socially mature enough” to seek advice on handling materials in his lab. Okamoto has told RIKEN officials that he did not bring any samples from the United States to Japan, let alone into the RIKEN labs. RIKEN is trying to trace the origin of all materials in Okamoto's lab; Ito says that, so far, it has not found any evidence of U.S. materials.

Ito and other RIKEN officials are particularly chagrined at the accusation that RIKEN acted as an agent of the Japanese government for economic espionage. “We have operated with extraordinary openness,” he says. RIKEN conducts collaborative research projects with institutions throughout the world, Ito says, and nearly a quarter of its 245 researchers are non-Japanese. “I am seriously worried about this incident having an impact on RIKEN's image,” he says.

2. THE POSTGENOMIC ERA

# Windfall for European Data Bank

1. Michael Balter

PARIS—The European Union has come to the rescue of the continent's premier repository of DNA and protein sequence information. As Science went to press, the E.U. was preparing to announce that it would help provide a roughly 50% boost in the $11 million annual budget of the European Bioinformatics Institute (EBI). The cash injection, to come over the next 3 years, will fund four new projects, including repositories of data from “gene chips” and protein-protein interactions. These projects, in turn, will help provide much-needed operating funds for EBI. This is the second major piece of good news that the financially troubled EBI, located near Cambridge, U.K., has received in the past 6 months. Last December, the governing council of the European Molecular Biology Laboratory in Heidelberg, Germany—EBI's parent organization—agreed to bail out the institute after E.U. officials had decided to stop funding routine operating costs for a number of European research centers (Science, 5 November 1999, p. 1058, and 8 December 2000, p. 1869). “This is a day for celebration,” says EBI co-director Graham Cameron. “It is the biggest dollop of money ever put into [European] bioinformatics infrastructure.” The groundwork for the E.U.'s generosity was laid last November, when Philippe Busquin, research commissioner at the European Commission—the E.U.'s executive wing—earmarked$22 million for genome projects involving databases and animal disease models. This week's announcement that a significant chunk of these funds will go to the EBI represents a partial relaxation of spending rules that some scientists feel are too stringent. “The struggle has been to fund research proposals that are not directly linked to the simple maintenance of databases,” explains Carlos Martinez-Riera of the research directorate. Indeed, both E.U. and EBI officials stress that the money was awarded only after the EBI and other partners submitted proposals for new programs rather than for ongoing costs. Although the philosophy behind the funding rules has not changed, Martinez-Riera says, the new EBI funding in practice will help sustain the institute. “We have met each other in the middle,” he says.

The E.U. money will fund four new projects: a database for information derived from “DNA arrays,” which monitor the expression of thousands of genes at once; a data bank of three-dimensional protein structures; a database of biochemical interactions between proteins; and a project to integrate several existing EBI databases so that researchers can conduct more sweeping searches. The EBI, slated to receive $11.3 million for these projects over the next 3 years, will carry them out in collaboration with 30 other labs in 11 European countries. EBI's partners will share an additional$5.7 million in E.U. funding.

“This kind of science creates its record in electronic form,” says Cameron. The E.U. funds, he says, should better position EBI to “carry on its crucial role as a custodian of this record.”

3. CLIMATE CHANGE

# 17 National Academies Endorse Kyoto

1. Jocelyn Kaiser

As the Bush Administration dithers over what it might do to address global warming, 17 national academies of science decided to cut to the chase in an editorial in this week's Science. Affirming the Intergovernmental Panel on Climate Change's (IPCC's) conclusion that human activities are warming the planet, the statement urges those with “doubts”—by implication, the United States—to ratify the Kyoto Protocol, which would impose binding limits on greenhouse gas emissions by industrialized countries (see p. 1261). Robert May, president of the Royal Society of the United Kingdom, which organized the statement, says it was partly provoked by Bush's recent rejection of the Kyoto treaty, along with resistance to the Kyoto terms from countries such as Australia.

Notably absent from the list of signers is the U.S. National Academy of Sciences (NAS). It was invited to sign, but the NAS board felt it could not endorse a document it did not help draft on a few days' notice, says F. Sherwood Rowland, NAS foreign secretary. According to several sources, the statement's explicit backing for the Kyoto Protocol was a problem. The protocol is “regulatory, not science,” Rowland says. The academy, moreover, is conducting its own expedited review of the IPCC report and did not want to be seen to prejudge the outcome. “This is a complicated subject, and the National Academy wants to hear from its chosen experts after having looked at it thoroughly,” says Rowland.

Many scientists—and indeed, the 17 national academies—think the IPCC did just that. Over 2500 scientists pored over data for 3 years, producing a massive, multivolume report that is the consensus of “the global expert community in the field of climate change, not some subset of it,” says May. In their statement the academies, including those of Australia, France, China, and India, write: “Doubts … expressed recently about the need to mitigate the risk posed by global climate change” are not “justified.” Ratification of the 1997 Kyoto Protocol “represents a small but essential first step” to halt the buildup of greenhouse gases.

White House officials, however, apparently question the IPCC's conclusions, and after “informal discussions,” NAS officials say, they decided to review them. Over the next few weeks, an 11-member panel funded by the NAS will try to answer questions that IPCC's Working Group I already covered. The panel will decide, for example, whether climate change is occurring, whether human-produced greenhouse gases are contributing, and how much temperatures will rise. NAS executive officer William Colglazier says that “obviously we're not going to redo the analysis that IPCC did,” but the academy is gathering the IPCC's technical documents and will issue its own “consensus statement.” He says the NAS doesn't doubt the IPCC's conclusions but simply feels it needs to analyze the evidence itself. “It would have been difficult for us to do an objective study” if the academy signed the statement, says Colglazier.

The panel includes seven academy members, including Rowland, a Nobel Prize winner for his research on ozone layer- destroying chemicals, as well as NASA's James Hansen, who has recently suggested adding soot to the pollutants that Kyoto targets, and Richard Lindzen, a meteorologist at the Massachusetts Institute of Technology and a global warming skeptic. The latter pair are part of a group of scientists who have been briefing Bush Cabinet officials weekly, offering a condensed Climate Science 101, says a White House spokesperson. Most panelists have also participated in the IPCC process. The panel will meet in a closed door, 2-day session in Irvine, California, next week and issue its report by early June. Until that time, the academy is remaining mum on climate change. Even then, says Rowland, it is unlikely to issue an opinion on the Kyoto Protocol.

The academy has already issued numerous reports on climate change science. And in a 1992 report called “Policy Implications of Greenhouse Warming,” an NAS panel urged the United States to launch “a concerted program to start mitigating the further buildup of greenhouse gases.” Some scientists speculate that the new study and the academy's reluctance to endorse the Kyoto treaty reflects changing times. “It is reasonable considering the political environment,” says Jack Townsend, a member of the National Academy of Engineering and retired head of NASA's Goddard Space Flight Center. He points out that NAS “is not independent in the sense that they receive government money to conduct studies. They can't tee off too many customers.”

The academy's hesitance on the Kyoto treaty is not shared by some of its members. Rowland and several other NAS members signed a letter organized by the Union of Concerned Scientists just before the December 1997 Kyoto meeting urging mandatory limits on greenhouse gas emissions. But another member who often speaks out on policy, Stanford ecologist Paul Ehrlich, says he understands the NAS's position. “As an academy member, I'm quite happy to say the Bush position is idiotic,” says Ehrlich. But the academy, he notes, was set up “to give scientific advice to the government” through its deliberate panel process and “has no mechanism for taking a position” on urgent policy issues.

4. RIBOZYMES

# Making Copies in the RNA World

1. R. John Davenport

By mimicking evolution in the lab, scientists have produced the first RNA enzyme that can make copies of other RNA molecules. The discovery provides a missing piece of evidence for a primitive biological world that existed before DNA and proteins entered the scene.

The discovery nearly 2 decades ago of ribozymes—RNA molecules that can catalyze chemical reactions—led to the idea that modern life could have evolved from a primitive “RNA world.” Doing the job of both DNA and proteins, RNA would carry genetic information and replicate that information to pass on to future generations. Subsequent discovery of additional ribozymes—including the heart of the protein-synthesizing ribosome (Science, 31 July 1998, p. 658, and 11 August 2000, p. 878)—has added to the credibility of the RNA world hypothesis. But scientists have been unable to show that molecules of RNA are actually capable of copying other RNA sequences, a job performed in the modern biochemical world by protein enzymes called RNA polymerases. That activity would be a critical component of an RNA world.

On page 1319 of this issue, Wendy Johnston and colleagues at the Whitehead Institute for Biomedical Research at the Massachusetts Institute of Technology (MIT) in Cambridge have now filled that key gap. They describe an enzyme, consisting of a stretch of RNA produced by in vitro evolution, that can make complementary copies of RNA molecules up to 14 nucleotides long, regardless of sequence, with impressive accuracy.

“The engine of the RNA world” would have to be able to do better than 14 nucleotides, says Gerald Joyce of the Scripps Research Institute in La Jolla, California, “but there's no doubt [now] that RNA [itself] is capable of doing polymerization.”

David Bartel, leader of the Whitehead group, had previously selected from random RNA sequences an RNA molecule that could join two RNA strands end to end. He later discovered that this “RNA ligase” could also add a few nucleotides, the individual building blocks of RNA, onto the end of RNA molecules with specific sequences. Although not very robust, the ribozyme was performing the same chemical steps as “modern” protein enzymes that synthesize RNA.

To search for ribozymes that are better at copying RNA, the Whitehead team made a collection of RNA molecules, each of which consisted of Bartel's RNA ligase ribozyme linked to a 76-base RNA with random sequence followed by an RNA “primer.” They screened 1015 of these randomized molecules for those that could add nucleotides to the end of the RNA primer, in a specific sequence dictated by an RNA template added to the reaction. The researchers amplified working molecules and retested them with different sets of primers and templates in multiple rounds of in vitro “survival of the fittest.” The result was a vastly improved ribozyme. Not only could it make complementary copies of RNA templates 14 bases long, but most important, it could use any RNA sequence as a template, a generality that would be critical for a replicating ribozyme in an RNA world.

Bartel notes that the ribozyme stops adding bases not because it can't hold onto long pieces of RNA but because the best reaction conditions for polymerization are also optimal for chemical breakdown of RNA. That suggests that by tweaking the reaction conditions it should be possible to make RNA molecules longer than 14 nucleotides—a prerequisite for the RNA world. (The Whitehead team's ribozyme itself, for instance, is 189 nucleotides long.)

The ribozyme adds the right base onto RNA about 98.5% of the time. That pales in comparison to protein polymerases, which can achieve 99.99% accuracy. But, speculates Phillip Sharp of MIT, ribozymes in the RNA world may have only had to copy RNA sequences a few hundred bases long; longer units could have been spliced together by other ribozymes. That would make higher error rates tolerable.

The ribozyme's ability to generically recognize any RNA sequence is likely due to its interaction with chemical groups on an RNA molecule's backbone. The details of that interaction, however, await further structural studies. Those studies could reveal similarities with protein polymerases, says biochemist Tom Cech of the University of Colorado, Boulder, president of the Howard Hughes Medical Institute and co-Nobel Prize winner for the discovery of ribozymes. He notes that protein polymerases commonly resemble a hand, with catalysis occurring in the “palm” and a “thumb” and “finger” holding the substrate in place: “Maybe they started with a palm [the RNA ligase] and evolved a thumb and finger.”

5. PALEONTOLOGY

# Early Tyrannosaur Was Small But Well Armed

For all the fame of Tyrannosaurus rex and its relatives, their origins have been difficult to pin down. Now paleontologists have unveiled a skeleton of a primitive tyrannosauroid that backs up what many have suspected: The hulking predators evolved from smaller, long-armed creatures with grasping hands.

The classic view of T. rex ancestry held that it evolved from a long line of large meat eaters that stretched back about 80 million years to the Jurassic. An alternative idea, proposed in the 1920s, suggested that the tyrannosaurs of 65 million years ago descended from a group of more diminutive predators called the coelurosaurs, which is now known to include Velociraptor. The theory didn't catch on at the time, but it was revived in the 1990s and sometimes dubbed the “tyrannoraptor hypothesis.” Yet despite the many anatomical similarities between tyrannosaurs and smaller coelurosaurs, no one had found a dinosaur that seemed transitional.

That gap is now filled by the 132-million-year-old Eotyrannus, found by an amateur collector in 1997 on the Isle of Wight, off the southern coast of England. Although isolated bones of primitive tyrannosaurs had been reported before, this 5-meter-long skeleton beats them hands down. It's about 40% complete and includes the front half of the skull. In the April issue of Cretaceous Research, a group from the University of Portsmouth, United Kingdom, and the Museum of Isle of Wight Geology describes several features that link Eotyrannus with tyrannosaurs, such as fused nasal bones and teeth with a “D”-shaped cross section. Other traits are much more primitive, and it has long arms and hands like Velociraptor—just as the tyrannoraptor theory predicts. “This is one of the first specimens to confirm that,” says team member Darren Naish of the University of Portsmouth.

The new specimen will help clarify how tyrannosaur traits evolved, says paleontologist Tom Holtz of the University of Maryland, College Park, who gave the tyrannoraptor hypothesis its name. For example, Eotyrannus implies that the advanced biting style of the tyrannosaurs evolved in a predator that could still grab with its arms. As for the tyrannoraptor idea, Holtz says Eotyrannus “is great confirmation.”

6. ANIMAL RESEARCH

# Charles River Labs to Care for NIH Chimps

1. Gretchen Vogel

After a yearlong search, the National Institutes of Health (NIH) has found a new caretaker for nearly 300 chimpanzees once used in medical research. The decision is a mixed blessing for animal activists. They had long accused the animals' current caretaker, the Coulston Foundation of Alamogordo, New Mexico, of unsafe and negligent veterinary practices, but they had hoped the chimps would be released to a retirement sanctuary. And they were especially upset by a separate NIH decision to purchase 14 young chimpanzees from Coulston for possible research.

As Science went to press, NIH was set to sign a 10-year, $42.8 million contract with Charles River Laboratories, a company based in Wilmington, Massachusetts. The corporation would assume care for 286 NIH-owned chimpanzees at the Holloman Air Force Base in New Mexico, most of them infected with HIV or hepatitis in NIH protocols. “This isn't an official sanctuary, but the idea is that at this facility, [chimpanzees] will be cared for, given social enrichment, and allowed to live out their natural lives,” says Charles River senior vice president Dennis Shaughnessy about the colony. No experiments will be conducted at Holloman, says Judith Vaitukaitis, director of NIH's National Center for Research Resources, although NIH-funded scientists interested in conducting research on the chimps may arrange for animals to be transported to other sites. Animal-welfare groups have complained loudly about the privately owned Coulston Foundation, charging that it provides inadequate veterinary care and keeps its animals in unsafe conditions. The foundation has denied those charges. In 1999, Coulston settled one investigation by the U.S. Department of Agriculture (USDA) into animal welfare violations (Science, 10 September 1999, p. 1649) by agreeing to give up 300 of the approximately 600 chimpanzees the foundation owned. NIH acquired 288 Coulston chimps last May and since then has conducted several unsuccessful searches for a caretaker. Coulston put in a bid, but NIH rejected its application (Science, 13 October 2000, p. 247). The USDA still has an open investigation on Coulston, and two of the NIH-owned animals have died in the last year. Animal-welfare groups have claimed that the deaths were due to negligence, whereas Coulston spokesperson Donald McKinney says that the animals died of routine health complications. Linda Brent, president of Chimp Haven, an organization in San Antonio, Texas, that hopes to build retirement sanctuaries for former research chimpanzees, says finding an alternative provider was a positive interim step. “I am hopeful that in the future [the chimpanzees] will be able to be moved out and fully retired,” she says. Indeed, NIH is reluctantly moving forward to set up a system of retirement sanctuaries. Last month, it requested that interested organizations describe their ability to care for at least 75 chimpanzees as part of the so-called CHIMP Act, which President Clinton signed into law last December (Science, 22 December 2000, p. 2233). The law requires NIH to set up a system of retirement facilities for animals no longer needed in research. At least two organizations, Chimp Haven and Primarily Primates, also in San Antonio, filed the required statement by the 15 May deadline. NIH's planned purchase of 14 young, uninfected chimps from Coulston for nearly$30,000 each is a less happy development for activists. Vaitukaitis says her office was concerned that the animals, among those still owned by Coulston, “would be sold to the entertainment business” if NIH didn't act. She says it is not yet clear where the young chimps, ranging in age from 1 to 2 years, will live, but they will be available for research if the need arises.

Animal activists complain that NIH is “adding more babies into a supply” that already exceeds demand, says Chris Heyde of the Society for Animal Protective Legislation in Washington, D.C. For its part, McKinney says that the company has no plans to sell its animals to the entertainment industry but would try to sell them to other research laboratories if NIH didn't buy them.

7. RUSSIAN UNIVERSITIES

# Centers of Excellence Get Big U.S. Boost

1. Richard Stone

CAMBRIDGE, U.K.—A unique experiment to improve Russian science has won a ringing endorsement: Two heavyweight U.S. foundations are plowing $12.5 million into an effort to create scientific oases in Russia's impoverished university system. The funding boost more than doubles the budget of the fledgling Basic Research and Higher Education (BRHE) Program, allowing it to expand from eight to 16 centers across the country. BRHE's aim is to help break down the firewall between the Russian Academy of Sciences' institutes—where much of the country's best research is carried out—and the universities, which tend to lack world-class scientists. Toward that end, the program gives university-based centers 3-year,$1.05 million grants for purchasing major equipment and supplies, with the stipulation that the center collaborate with academy researchers. These are huge amounts—as much as 20% of a recipient university's annual budget. A key to sustaining the centers is to involve young scientists; this the BRHE ensures by mandating that 10% of center funds be distributed as grants to scientists who have received a Ph.D. or the Russian equivalent within the past 6 years.

BRHE debuted in 1998 with a 1-year pilot project: a center for scanning probe microscopy at Nizhny Novgorod State University, 400 kilometers east of Moscow (Science, 29 May 1998, p. 1336). BRHE has since expanded to seven more universities, from a center on nonlinear dynamics in Saratov, southeast of Moscow, to a marine biology center in Vladivostok, in Russia's Far East. One goal of the peer-reviewed program has been to beef up science outside Moscow and St. Petersburg; universities from these two powerhouses have been prohibited from competing for BRHE funds.

View this table:

The initiative has also required the Russian federal government and local authorities to pony up half the funding for each center. The fact that Russia has come up with every ruble it has pledged “tells us that we're responding to a need that's real,” says Gerson Sher, president of the Civilian Research and Development Foundation, an Arlington, Virginia-based nonprofit that runs BRHE with Russia's Ministry of Education. The eight centers are blossoming, adds Marjorie Senechal, a mathematician at Smith College in Northampton, Massachusetts, who attended a conference in Nizhny Novgorod last September to review the program's progress.

The new money announced last month—$11.5 million over 5 years from the John D. and Catherine T. MacArthur Foundation and$1 million over 2 years from the Carnegie Corp. of New York—will allow the BRHE to give 2-year extensions to some existing centers as well as add four centers in the Russian provinces. The new funding will also open up the peer-reviewed competition to Moscow and St. Petersburg, each of which will get two centers. The first winners will be announced in November, with another four centers to be chosen in 2002.

The BRHE's rising fortunes should help dispel the gloom that some scientists in Russia are feeling over the impending demise of another major Western effort: the 7-year-old International Soros Science Education Program, which has, among other things, provided stipends to 3750 university professors, high school teachers, and students in Russia, Ukraine, Belarus, and Georgia. The billionaire financier George Soros, who has sunk $109.5 million of his own fortune into the program, has said that this is the last year he will support it. Georgia's president, Eduard Shevardnadze, and others are lobbying Soros in the hopes he will change his mind. 8. GENOMICS # New Genomes Shed Light on Complex Cells 1. Elizabeth Pennisi COLD SPRING HARBOR, NEW YORK—Biologists have long wondered what genes separate the men from the boys—that is, the complex eukaryotes from the more primitive prokaryotes. Now they are beginning to find out, thanks to new work deciphering the genome sequences of higher organisms. At a genome sequencing and biology meeting last week,* researchers announced that they have decoded the genetic complement of a second yeast and are in the midst of sequencing two fungi. Already, these three new genome sequences are shedding light on what it takes to be a eukaryotic cell, says Paul Nurse, director of the Imperial Cancer Research Fund in London. By determining which genes these varied organisms have in common and removing those that are also shared by prokaryotes, he and his colleagues have identified the subset of genes that make possible more complex cell functioning. Yeast, fungi, and all multicellular organisms—from plants to humans—are eukaryotes, with complex cells that have discrete subunits, such as the nucleus and mitochondria, to help with various tasks. For decades, cell biologists have studied yeast, simple, one-celled organisms, for insights into how they and more complex eukaryotes work. Toward that end, in 1996, the yeast research community decoded the genome of the budding yeast, Saccharomyces cerevisiae. Now a European consortium of 12 labs led by the Sanger Centre in Hinxton, United Kingdom, has sequenced and analyzed the 14-million-base genome of Schizosaccharomyces pombe, also known as fission yeast. The team has even determined three-quarters of the bases in a hard-to-sequence region, called the centromere, that is critical to the proper replication and separation of chromosomes during cell division—a feat few other groups have accomplished on any genome. Of all the eukaryotes sequenced to date, fission yeast “has the smallest number of genes,” with 4944 predicted, Nurse reported at the meeting. Budding yeast has 5805 predicted genes, while humans have some 37,000, by the latest count. Even some lowly bacteria, such as Pseudomonas, have more than 5000 genes. That makes it clear, Nurse says, “that being a eukaryote doesn't simply depend on the number of genes, but the type and context.” Fission yeast is “a stripped-down eukaryote,” says Nurse, and as such, it likely contains the bare essentials of the eukaryotic cell, along with genes that define it as a fission yeast. To check this out, Nurse and his colleagues analyzed which genes fission yeast shares with the other sequenced eukaryotes. (These include the budding yeast, human, the plant Arabidopsis, the fruit fly Drosophila melanogaster, and the nematode Caenorhabditis elegans.) With yeast in the six-way comparison, Nurse eliminated genes that in humans and worms, for example, support multicellularity, as well as those genes that help define each species. They then excluded all the genes that fission yeast shares with prokaryotic bacteria or archaea. Those genes that remained are “a first step toward defining the eukaryotic cell,” says Nurse. Eukaryote-only genes include, for example, those that encode proteins involved in the spatial organization of the cell. Other genes produce proteins that help move molecules around and through membranes within a cell. Some code for proteins that organize chromosomes within the nucleus or regulate cell division, while others encode proteins involved in breaking down other proteins. Eric Green, a geneticist at the National Human Genome Research Institute in Bethesda, Maryland, calls the new work an “exciting first pass” that hints at the power of comparing genome sequences to learn not only about what distinguishes eukaryotes from prokaryotes but also about what sets various eukaryotes apart. “It illustrates the exciting analytical glasses that we are going to be able to put on,” he adds. In related work, a team from the Center for Genome Research at the Whitehead Institute in Cambridge, Massachusetts, has taken a first pass at the genome of the fungus Neurospora crassa, another model organism. And the Department of Energy's Joint Genome Institute in Walnut Creek, California, has sequenced and assembled almost 30 million bases of the genome of the fungus Phanerochaete chrysosporium. These fungi have much larger genomes and, presumably, more genes than fission yeast. Comparing these fungal sequences to those of yeast and others will help define the genetic underpinnings of that branch of the eukaryotic family tree. • *Genome Sequencing and Biology was held in Cold Spring Harbor, New York, 9 to 13 May. 9. VOLCANOLOGY # Oregon's Rising, an Eruption to Follow· 1. Richard A. Kerr When a parcel of land including a trio of volcanoes swells upward by a tenth of a meter over 4 years, volcanologists tend to get excited. That's exactly what's happened in the U.S. Pacific Northwest. By excruciatingly precise comparison of satellite radar data, they've discovered a broad, 10-centimeter-high uplift on the flanks of the Three Sisters volcanoes in the Cascade mountain range of central Oregon. No one can say what, if anything, will happen next—the most dramatic possibility is continued doming and an eventual volcanic eruption. But researchers are thrilled to be in on the ground floor of what could become a classic case study in volcanology. Usually, volcanologists arrive on the scene after the ground has begun to shake or, rarely, even as gas and ash are spewing out. Around the Three Sisters—North Sister, Middle Sister, and South Sister—35 kilometers west of Bend, Oregon (population 52,000), there is no geologic sign of such untoward activity in the past 1000 years or more. But as part of the U.S. Geological Survey's Cascades volcano monitoring duties, geophysicist Charles Wicks and his colleagues at the USGS office in Menlo Park, California, were using interferometric synthetic aperture radar (InSAR) to search for any change in the shape of the Cascades. Like ordinary radar, a satellite-borne SAR measures the distance to the surface by clocking the travel time of a microwave signal bounced off the surface (Science, 28 June 1996, p. 1870). Taking data from overflights of European Earth Resources Satellites in 1996 and 2000, Wicks and his colleagues measured the change in the distance to the surface during the 4 years by letting the two slightly out-of-phase signals interfere with each other to form an image of interference fringes. Each rainbow fringe in an interferogram would represent a rise or fall of the surface of 28 millimeters over the 4 years, at least where snow, dense vegetation, and soil moisture variations didn't intervene. What the InSAR analysis produced was a stunning bull's-eye of interference fringes centered 5 kilometers west of the South Sister volcano. Fifteen to 20 kilometers across and 10 centimeters high at its center, the uplift could have formed as magma oozed up into the crust within 7 kilometers of the surface; in fact, geophysicists are hard-pressed to think of any other explanation. “This came as a shock,” says volcanologist C. Dan Miller of USGS's Cascades Volcano Observatory (CVO) in Vancouver, Washington. “We had no idea anything was going on in that part of the world. We may have caught an eruption in the very earliest stages.” Eruptions have certainly happened before near the Three Sisters. “Every bump around there is a volcano,” says William Scott, scientist-in-charge at CVO. “It's what central Oregon is famous for.” Beyond the Three Sisters, which last erupted with lots of ash about 2000 years ago, there are hundreds of volcanic vents and cones that have briefly spewed less explosive lavas as recently as 1200 years ago. If such magma reached the surface at the bull's-eye, which is in the Three Sisters Wilderness, the hazard would be largely limited to the immediate vicinity, says Scott. If the magma turned out to be the more explosive sort, ash could blow downwind toward Bend or flow down streams as searing ash clouds or muddy floods for many kilometers. USGS researchers should have some answers by summer. They are moving equipment, including a seismometer and a telemetered Global Positioning System (GPS) receiver, into the sparsely instrumented region as the winter's snow recedes. GPS should tell them within a few months whether a rapid uplift is continuing. If it is, they'll want to be ready should any of the Three Sisters or their relations awaken. 10. ASTROPHYSICS # Star-Cluster Census Shows Surprises 1. Andrew Watson* 1. Andrew Watson writes from Norwich, U.K. The ancient balls of stars known as globular clusters are a favorite place for astronomers to test ideas of stellar evolution. Born in the dark ages before our own sun, globular clusters contain many old, heavy stars concentrated at their cores. Those central regions are so star-rich that near-collisions abound, and heavy stars frequently grab companions to form binary star systems that can reveal crucial information about the history and destiny of the cluster. Astrophysicists trying to understand the intricacies of the globular heart have a new weapon: the Chandra X-ray Observatory, uniquely equipped to spot the x-rays emitted by many of the core's inhabitants. Past x-ray studies revealed little more than a flecked smudge compared with new results reported online by Science this week (www.sciencexpress.org) from a team at the Harvard-Smithsonian Center for Astrophysics (CfA), which has used Chandra to produce a sharp, color-coded x-ray map of a core. “It is a big step in x-ray astronomy to have actually resolved what is happening in the middle of a globular cluster,” says Andrew Fabian of the Institute of Astronomy in Cambridge, United Kingdom. Although radio astronomers and the Hubble Space Telescope have uncovered many secrets of cluster cores, resolving individual x-ray sources and their energies is something new, Fabian says. The cluster, known as 47 Tucanae, is one of about 150 globular clusters sprinkled through our galaxy. The million or so stars in each are made of the material from which our galaxy grew. Because stars in a cluster all formed at about the same time and are all at about the same distance from Earth, globular clusters are a perfect space lab for astrophysicists to study how stars mature as they age. Heavier stars, more than eight times the mass of our own sun, have collapsed via a cosmic firework display—a supernova—into neutron stars. Many lighter cluster residents, their fuel likewise exhausted, have crumpled under their own weight to form white dwarfs. But stars in clusters don't merely grow old; they also learn to tango. “Clusters are so incredibly dense in their cores that stars are, in the everyday vernacular, nearly smacking into each other,” says Jonathan Grindlay of CfA, who led the new study. As a result, he says, “globular clusters are binary factories,” creating new double stars or swapping partners in existing binaries even today. In a typical binary pair, a small, dense partner—a neutron star or white dwarf—sucks material from its larger but less massive companion. As this accreted material crashes into the smaller star, it heats up, emitting x-rays. Different types of x-ray emitters have distinct x-ray signatures, but only Chandra has both the crisp vision and energy discrimination to pick out and label individual sources. As a result, it can provide information about neutron stars and accreting white dwarfs that has been “sorely lacking,” says astrophysicist Sterl Phinney of the California Institute of Technology in Pasadena. Grindlay and his collaborators, Craig Heinke, Peter Edmonds, and Stephen Murray, set out to use Chandra to survey the relative numbers of x-ray sources in the well-studied globular cluster 47 Tucanae— “everyone's favorite globular cluster,” according to Phinney. In the central core of the cluster alone, they picked out 108 distinct x-ray sources. By setting out the whole sample on an intensity-color diagram—an x-ray analog of the brightness-color diagram that optical-light astronomers use to classify stars—they claim to be able to estimate the relative numbers of four different types of x-ray sources in the cluster's core. About half are millisecond pulsars (MSPs), in which the x-ray pulse, with a period of just a few milliseconds, comes from a neutron star that spins madly after gobbling mass from its ordinary-star companion. About 30% are accreting white dwarfs, also dubbed cataclysmic variables, which are binaries comprising a white dwarf and an ordinary star. Some 15% are pairs of ordinary stars, while just two or three are what's termed quiescent low-mass x-ray binary (LMXB) stars, neutron star-ordinary star combos that accrete slowly and brighten up at intervals. The sheer number of neutron stars “is really a bit of a surprise,” Grindlay says. Those plentiful neutron stars derive from heavy stars, but astrophysicists expect that clusters should contain many more lightweight stars than heavy ones. Not only that, but neutron stars, freshly forged in a supernova inferno, travel at speeds of several hundred kilometers per second—so fast that they should just “zip out” of a cluster, Grindlay says. But Fabian thinks the problem may be an illusion. Relatively lightweight white dwarfs may well outnumber neutron stars in the cluster, he says. But because they emit few x-rays and don't form pulsars, the x-ray census may simply have undercounted them. Another mystery is why MSPs so vastly outnumber the handful of LMXBs. Independent evidence suggests that MSPs are the children of quiescent LMXBs, and many astrophysicists believe such transformations can run backward as well. If so, the population of MSPs and LMXBs should show a delicate balance, Grindlay explains—a balance that Chandra does not see. The new results instead support alternative routes for the creation of MSPs, Grindlay says. Perhaps the pulsars result from the direct collapse of accreting white dwarfs. Or perhaps—as Fred Rasio and Saul Rappaport of the Massachusetts Institute of Technology have suggested—LMXBs made a one-way transformation into MSPs long, long ago. In any case, astrophysicists agree that puzzles, at least, are one thing 47 Tucanae is likely to keep producing in abundance. 11. NEUROSCIENCE # Boosting Brain Activity From the Outside In 1. Laura Helmuth Stimulating the brain with magnetic fields is not only a useful research tool but can apparently alter cognition and ease depression. But exactly how it works is a bit of a mystery Recent claims about the powers of a brain stimulation technique might sound like testimonials for healing crystals. Fights depression! Speeds reaction times! Enhances reasoning abilities! But despite the link to magnets, which have long inspired goofball theories, so-called repetitive transcranial magnetic stimulation (rTMS) is being described not in the back of astrology magazines but in articles in journals such as The Lancet, Neurology, and Science. A slew of recent clinical trials in the United States and abroad has indicated that rTMS can lift depression in some patients who are resistant to other types of therapy. Canada's Health Ministry is convinced; in March it approved the technique for treating people with major depression. The U.S. Food and Drug Administration is considering a similar move; for now, the treatment is only available in the United States in clinical trials. So far, no one is claiming that rTMS will help you lose weight fast, but a few studies have suggested that it can also ease symptoms of schizophrenia, obsessive-compulsive disorder, and Parkinson's disease, although these findings aren't as well established as those on depression. And one recent study even shows that well-aimed rTMS can speed one's ability to solve puzzles. Since it was introduced in 1985, rTMS has been used mostly as a research tool to figure out what different parts of the brain are doing and how they interact. Researchers still don't completely understand how rTMS modifies brain activity, but its ability to do so is well established. “This is a great neuroscience tool for testing the relationship between brain and behavior,” says neurologist and psychiatrist Mark George of the University of South Carolina, Charleston. George helped conduct the first study showing rTMS can relieve depression, and that has opened the door to using this therapy as a potential treatment for other psychiatric disorders. “We're just beginning to understand how to use it,” says George. ## Charging neural batteries The rTMS technique is a fairly noninvasive way to stimulate brain tissue, George says. It works because neurons are in some sense electric creatures: They fire in response to changes in the concentration of charged particles inside and outside the cell. People have known for years that direct electrical stimulation can cause neurons to fire (see photo below). The trouble is that it hurts; direct electrical stimulation zaps pain-sensitive neurons in the scalp and thus tends to scare away research subjects. In contrast, rTMS gooses neurons indirectly and painlessly. Repeated pulses of electric current are sent through a metal wire, which is usually round or figure-eight-shaped. This electric current generates a perpendicular magnetic field. (Remember the right-hand rule from physics class.) The magnetic field, in turn, generates another electric current in nearby material—in the case of rTMS, the current runs through brain tissue just below where the coil is placed on the scalp (see illustration). If the induced electric current is strong enough, it can overwhelm neural communication in the tissue where it is focused and cause a “temporary lesion.” Many single-burst (as opposed to repetitive) TMS studies marshal this power to test whether a specific brain region contributes to a given task; for instance, zapping the visual cortex has been shown to interfere with visual imaging (Science, 2 April 1999, p. 167). Under the right circumstances, however, repeated applications have a longer lasting effect than a single burst of stimulation. To get this effect, researchers first calibrate the intensity of the magnetic stimulation by placing the coil over a person's motor cortex. They move the coil around and adjust the intensity until they find what George calls “the sweet spot”—a region of motor cortex that, when stimulated, causes the thumb to twitch. The researchers then use the twitch-inducing intensity to deliver repeated pulses to other parts of the scalp. In general, low-frequency stimulation of about 1 to 5 pulses per second tends to depress brain activity afterward; higher frequency stimulation of about 25 pulses per second increases excitability. Both effects last about twice as long as the initial stimulation, that is, for a few minutes to about an hour. Why different stimulation frequencies trigger different responses in nearby neurons is “absolutely unclear,” says Eric Wassermann, chief of the brain stimulation unit at the National Institute of Neurological Disorders and Stroke (NINDS) in Bethesda, Maryland. But researchers and clinicians can take advantage of the lingering buzz. ## Detour for depression circuits Although rTMS can spark an electric current in the brain, it's nowhere near as powerful as a better known treatment for depression: electroconvulsive therapy (ECT). Shock therapy fell out of favor because of its often severe side effects, but it can cure stubborn cases of depression. It works by causing a seizure. “After a seizure, all brain function is radically changed,” Wassermann explains, and somehow that kicks the brain out of its depressive rut. In testing rTMS, says Wassermann, “our idea was to [change brain function] in a focal way, incrementally.” Wassermann and others have found that, compared to sham stimulation, tickling the left prefrontal cortex with rTMS relieves depression in some people who haven't responded to drugs or other treatments. The target, near the top of the forehead, isn't arbitrary; in functional imaging studies “the lateral prefrontal cortex comes up again and again as part of the mood circuit underlying depression,” says psychiatrist Holly Lisanby of Columbia University in New York City, who has conducted rTMS studies on Parkinson's disease and other disorders. The left prefrontal cortex is less active in people with depression, and neuroimaging studies show that rTMS gives it a boost. In a standard clinical trial, a depressed patient receives rTMS over the left prefrontal cortex for 20 to 30 minutes once a day for 2 to 4 weeks. Most studies to date have used this model, even though it's “based on something Mark George and I pulled out of a hat,” says Wassermann. “It's implausible that we stumbled on the most effective combination” of stimulation frequency, intensity, timing, and location, cautions George. But as Wassermann points out, there's not a lot of funding directed at perfecting clinical rTMS techniques. Unlike drug companies, Wassermann says, “the equipment manufacturers' [pockets] are not deep.” Most studies have been funded by private institutions or the National Institutes of Health. In this and other applications, the stimulation is probably not easing depression simply by juicing up the neurons directly below the coil. As neurologist Alvaro Pascual-Leone of Harvard Medical School in Boston points out, rTMS is “not a light form of ECT but a way of modulating a circuit.” In depression, the left prefrontal cortex is connected to a network of maladjusted brain areas. “I think a lot of the therapeutic effect we're seeing is not related to stimulation of the area we're targeting,” speculates Pascual-Leone. “But through there, we're getting access to the limbic system,” which decades of research have implicated in the regulation of emotions. If rTMS can indeed jump-start—or calm— entire neural circuits, many disorders might yield to targeted stimulation, Lisanby says. Researchers can determine through functional neuroimaging where a circuit rises to the surface of the brain and focus treatment there. In schizophrenia, for example, a study reported last year in The Lancet showed that low-frequency rTMS to the temporoparietal cortex (above the ear) reduced auditory hallucinations. Such studies are in their early stages, but “the field is aggressively pursuing” the strategy, Lisanby says. ## Faster thinking with rTMS· Neurological and psychiatric disorders aren't the only brain processes that affect wide-ranging neural circuits. Speaking, seeing, and problem solving, along with most mental tasks, activate some tissue deep in the brain and other bits at the surface. Once researchers showed that rTMS could alter mood, the logical next step was to see whether “we could do the same thing for any process stored in the brain,” says cognitive neuroscientist Jordan Grafman of NINDS. In the past few years, for instance, researchers have found that delivering rTMS to speech areas of the brain can take the words right out of someone's mouth; specifically, people name pictures faster after the treatment. And rTMS applied to motor areas facilitates lightning-fast movements. Grafman's group has turned its attention to more abstract brain processes, as they reported in Neurology this year. They asked people to solve analogy puzzles, in which they had to figure out the relationship among a group of colored geometric shapes and then pick out the analogous pattern in other sets of shapes. Positron emission tomography (PET) studies show that the prefrontal cortex, among other areas, lights up when people perform such a task. Sham stimulation or rTMS to other areas of the brain shortly before presenting the puzzles didn't help people solve them, but rTMS to the prefrontal cortex speeded subjects' insights. So far, no studies have answered just how rTMS might facilitate thinking, Grafman says. He suggests that rTMS might raise the baseline level of neural activity in a region just enough so that neurons don't have to work as hard to retrieve a memory or a problem-solving strategy. One of the barriers to figuring out how neurons respond to rTMS is the lack of animal models, says George. Whereas researchers can easily dilute a drug to rat strength, they can't yet make an effective miniature rTMS coil. At smaller sizes, the coil can't create a magnetic field strong enough to induce a current in the rat or monkey brain that's as strong as the current induced by a full-size coil. “It's a real materials science problem,” says George. In addition to neurobiology, Wassermann notes, plenty of other effects of rTMS aren't well understood. The procedure appears to be safe at the mild intensities used in the lab, and rTMS passed all its safety studies shortly after it was introduced. But if the technique is powerful enough to ease depression and have other possibly long- lasting clinical effects, researchers should be more diligent about including safety studies whenever they use it, Wassermann cautions: “Anything that works well can cause significant side effects.” But if researchers can live with a certain amount of neurobiological ambiguity and are willing to test the safety of the technique as they go, rTMS is a fairly affordable and therefore democratic tool—especially for neuroscience hardware. A complete setup runs$30,000 to $40,000, compared to$1.5 million and up for functional magnetic resonance imaging. It's still a young field with plenty of unanswered questions and wide-open neural territory to explore. But if the words “brain stimulation” and “inexpensive” bring improper thoughts to mind, be warned: Those neurons that buzz when someone takes euphoria-inducing drugs or eats ice cream are buried deep in the brain, beyond the reach of rTMS. “We've tried,” jokes George, “but there's no way to get a pleasure-center stimulation with the current technology.”

12. SCIENCE EDUCATION

# Creationism Takes Root Where Europe, Asia Meet

1. Robert Koenig

Harassed but hard-headed, some gutsy Turkish scientists are stepping up their efforts to promote the teaching of evolution

ANKARA—When Aykut Kence opened his mail one November morning in 1998, he was startled to find his face on the front page of a newsletter next to the stern visage of Chinese Communist leader Mao Zedong. After reading the article, which denounced the Turkish biologist as a leftist supporter of Darwinism, his wife Meral, also a biologist, joked: “Aykut, I've known you for 30 years, and you never told me that you were a Maoist.” Kence chuckled: He subscribes to Darwin's theories, but hardly to Mao's.

It was no joke, however, when Kence and five other Turkish scientists became targets in a campaign to promote creationism and discredit Darwinism spearheaded by the Istanbul-based Bilim Arastirma Vakfi (BAV), which translates as the innocuous-sounding “Science Research Foundation.” After being “outed” as Darwinists, Kence, a professor at Middle East Technical University here, and his colleagues began receiving anonymous threats, and they responded by suing BAV for defamation. They won: In 1999, Ankara Civil Court awarded them $4000 each in damages. Although heartened by that legal victory, many scientists here fear they are losing ground to Turkish creationists in the wider court of public opinion— especially in provinces where Islamic fundamentalism is strongest. The defamation case and an unrelated investigation of key BAV members have not stopped the group's vigorous crusade—experts call it the best organized and financed in the Islamic world—to discredit the teaching of evolution. The group's few hundred active members, mostly volunteers, have developed a Web site and enlisted speakers from U.S.-based creationist organizations to appear at antievolution events across Turkey. They've also swamped the country with sophisticated books such as The Evolution Deceit and The Dark Face of Darwinism (both published under the pseudonym Harun Yahya), which some scientists complain have become more influential than textbooks in certain parts of the country. Nor is BAV the only face of Turkish creationism. A medical professor and member of parliament, Ali Gören, recently launched a legislative drive to drop the teaching of Darwin's evolution theory in secondary schools. Labeling Darwinism a “scientific fraud,” Gören—whose Virtue Party, the third-largest in parliament, has Islamic ties—urged fellow legislators this spring to protect high-school students from evolution theory's “adverse affects,” which he claims encourages “atheism and separatism.” Although many scientists deride Gören's initiative as doomed to fail in the current parliament, they worry that Turkey's mounting economic woes could give right-wing nationalist and Islamic fundamentalist parties—both of which tend to support creationism—a boost in the next elections. “The creationists have access to lots of money, and the political situation is in turmoil,” says conservation biologist C. Can Bilgin of Middle East Technical University. “We can't take anything for granted.” Echoing his concern are medical geneticist Isik Bökesoy of Ankara University —who has been lambasted in fundamentalist publications for her defense of evolution theory—and Kence, who received an anonymous e-mail last month suggesting that he “enjoy [his] final days.” Such venom has only served to harden the researchers' resolve to protect the fragile status of evolutionary theory in Turkish schools. They are organizing public declarations and have rallied the Turkish Academy of Sciences to their cause. “I won't let them silence me,” Kence says. “If knowledgeable people keep quiet, it only helps those who spread nonsense.” ## An evolving mindset The debate over evolution and creationism is a microcosm of a wider battle—the struggle between secularism and Islam—that has raged ever since Kemal Atatürk created the secular Turkish Republic in 1922. Indeed, the emphasis on creationism in textbooks has waxed and waned with the fortunes of Islamic political parties. Creationism first made its mark in Turkish schools in 1985, when then-Education Minister Vehbi Dincerier ordered a section on “scientific creationism” added to high-school textbooks. His ministry also decreed that Lamarckism be taught alongside Darwin's evolution theory—and that the texts include criticisms of both theories. Some biologists argue that playing up the largely discredited theory of 19th century French naturalist Jean-Baptiste Lamarck—who asserted that evolution occurs when parents pass on to their offspring characteristics acquired during their lifetimes—casts a poor light on evolutionary science in general. Over the next decade, Kence and his allies tried to get the textbooks changed. They were stymied until after the fall of the short-lived (1996–97) government of former Prime Minister Necmettin Erbakan, a leader of the now-banned Welfare Party who backed Islamic creationism. Not until a new education minister, Hikmet Ulugbay, was appointed did Kence's group win a partial victory: High-school biology texts issued since 1998—while mentioning creationism and Lamarckism—give a more balanced presentation to Darwin's theories. Those textbook changes infuriated BAV and its backers, who mobilized by organizing seminars across Turkey in 1998–99 and giving away thousands of Yahya's Darwin-bashing tracts. Antievolution groups “have tried a number of times to drop the teaching of evolution at public schools,” says zoologist Dincer Gülen, dean of the science faculty at Istanbul University. “They think they are making scientific arguments, but in fact it is theological philosophy, and unfortunately some scientists believe in that as well.” Yet BAV does not appear to be a bastion for gray beards or backward zealots. “The BAV members I met were mainly young professionals who described themselves as Islamic moderates who are trying to harmonize the Koran with science,” says science historian Ronald Numbers of the University of Wisconsin, Madison, author of The Creationists. He's one of the few U.S. experts who has interviewed the group's “honorary president,” Adnan Oktar, who according to BAV writes the Yahya books—many of which have been translated into English. BAV did not create a movement from scratch. It has borrowed heavily from the playbook of like-minded U.S. groups, says neurologist Umit Sayin of the University of Wisconsin, Madison, who has analyzed Turkish creationism. One organization with ties to Turkey is the Institute for Creation Research in Santee, California. The institute's John D. Morris—who has visited Turkey on expeditions in search of Noah's ark on Mount Ararat—told Science that his outfit had supported the Turkish cause mainly by sending information. “They have read our material and restated it in the Turkish context,” says Morris, who along with several other U.S. creationists has spoken at BAV-sponsored seminars. Although both Christian and Islamic takes on creationism contend that evolution theory can be disproved by scientific evidence, there are some differences in the approaches. The Koran, for instance, does not give a time frame for creation. Although Morris concedes that “Islam is not as explicit” in outlining creation, he says that Christian and Muslim creationism nevertheless “are compatible.” After a remarkable rise in influence, BAV suffered a big blow: In late 1999, Oktar and others with the group were arrested on blackmail charges unrelated to the creationist movement. Their leader's incarceration energized claims by Turkish creationists that they—rather than the pro-evolution scientists they criticize—are victims of persecution. “Our intellectual effort against materialism has created an unjust opposition to our foundation,” claims a BAV spokesperson, Istanbul-based Internet businessman Mustafa Akyol. He blames Oktar's arrest and 9 months in prison before the leader's recent release on anti-BAV efforts by “evolutionists” and liberal newspapers. Despite that setback, experts say BAV has developed one of the world's strongest antievolution movements outside of North America and has been making inroads in other Muslim nations. Says physicist Taner Edis of Truman State University in Kirksville, Missouri, who has written extensively on Turkish creationism: “From what I've seen, their international outreach has become a priority.” ## Evolution as a flash point Kence and other scientists have tried to mount an organized response to the growing creationist sentiment. In 1998, Kence helped establish the Evolution Group, a handful of Turkish scientists who took it upon themselves to better explain to the public the scientific basis of evolution theory. After BAV organized more than 100 creationist seminars across Turkey in 1998 and 1999, the Evolution Group made two public declarations against antievolution arguments and gathered the signatures of more than 2000 university professors, scientists, and members of the Turkish Academy, which issued its own declaration in defense of evolution. This summer, the academy plans to distribute 3000 copies of a new Turkish version of the U.S. National Academy of Sciences' educational booklet, “Science and Creationism.” It will go to biology teachers, parliamentarians, and the media, says Sevket Ruacan, director of Hacettepe University's Institute of Oncology and the academy's point man on evolution education. “We will fight any effort to drop the teaching of evolution from our textbooks.” Despite such initiatives, rallying support for evolution has been difficult. Sayin, who was part of the group that sued BAV, contends that “the academics and universities are unfortunately very silent and sluggish.” And with creationists represented in several parties in parliament, Turkey's Scientific and Technical Research Council, called TUBITAK, has steered clear of confrontations with evolution opponents. “When you consider the number of biologists in Turkey,” says Bilgin, “you would expect a greater response to such creationist nonsense. But you don't hear from many of them. They are either afraid of speaking out, or they think the issue will fade away.” Kence is an exception. Two years ago, he convinced his university to put up a bronze bust of Darwin in front of the biology building. And this March he penned an open letter to parliament objecting to Gören's initiative to drop evolution from textbooks—a letter that sparked a slew of hostile e-mails. “I've gotten used to the threats,” he says, nodding to a sign taped on his office wall: “To Avoid Criticism: Do Nothing, Say Nothing, Be Nothing.” 13. PROFILE # Shirley Tilghman: Princeton's Unconventional New Chief 1. Eliot Marshall Next month, this expert on gene silencing and advocate of women in science will become the first woman president of Princeton University Fifteen years ago Shirley Tilghman, then a single mother with two young children, was working at the Institute for Cancer Research of the Fox Chase Cancer Center in Philadelphia. Battling traffic, “I spent hours every day driving between work and kindergarten and home,” she recalls. Life was getting “impossibly complicated.” At the same time, “I had a feeling I was becoming very narrow” academically. Everything got simpler in 1986 when Princeton University offered her a job in the biology department. The university seemed “perfect,” she recalls, not only because it enabled her to start afresh in basic biology (she had been a biochemist at Fox Chase), but also because there was no commute. To her delight, she discovered she could drive “anywhere in 3 minutes,” leaving her more time for research, family, and students. Tilghman says: “I knew I was a good teacher; I wanted to teach, and I liked the fact that Princeton considered teaching a really serious part of the job.” Tilghman's move in 1986 was a boon for the university as well. Two years after arriving she became a Howard Hughes Medical Institute investigator. Her work in mammalian genetics won recognition and honors, including membership in the National Academy of Sciences (NAS). In 1998, Princeton asked her to head a new interdisciplinary institute, endowed with$70 million, that would integrate biology, physics, mathematics, and engineering. And this spring, just as bulldozers began digging a foundation for the institute, Princeton made another offer: Would she like to run the university· She decided she would. On 15 June, Tilghman will become Princeton's first woman president.

Scientists on and off campus applaud the choice. Tilghman “never shies away from asking the kinds of questions that turn things topsy-turvy; questions that make you realize that, just because we've always done it this way, doesn't mean we should continue doing it,” says Maxine Singer, a biologist and president of the Carnegie Institution of Washington in Washington, D.C. This openness, Singer says, “makes her a wonderful scientist.”

Singer first met Tilghman 2 decades ago when she arrived as a postdoc at the National Institutes of Health (NIH) to work in Philip Leder's lab. There, Tilghman helped clone the mouse beta-globin gene, the first mammalian gene cloned, revealing its complex structure. Tilghman continued working on mammalian genetics at Fox Chase and Princeton. Today she's best known for studies of imprinting, the process by which genes from the mother or father are “silenced” to allow expression of the other parent's genes. Researchers had observed the phenomenon earlier, Singer notes, but “a lot of people didn't take it very seriously.” Tilghman's research “put it on a sound molecular basis … and made people sit up and realize that this was important—that epigenetic effects are much more prevalent than we had realized.”

Gene silencing can occur in many different ways, Tilghman notes. Recently, her lab and Gary Felsenfeld's group at NIH have been studying how a protein called CTCF plays a reciprocal role with methylation to permit or block expression of a gene, depending on the gender of the gene's source. The intricacy of this system—and new information about the number of different proteins that can come from a single gene—suggests that DNA may be extravagantly variable in the way it functions. Tilghman says: “I am taken these days with the idea that cells program in sloppiness as a diversity-generating mechanism—that they are not nearly as precise a machine as we thought.”

Leaving behind this research is “the most difficult part” of becoming Princeton's president, Tilghman says. She plans to keep her lab “active and open” until the current trainees are through in a few years. Another hard task, she says, will be to find a new chief for the Lewis-Sigler Institute for Integrative Genomics, which she has been developing since its inception 2 years ago. She has recruited several faculty members, looking for scientists who can collaborate easily and are willing to merge fundamental theory with precise observation. Two of her early recruits, for example—physicist Stanislas Leibler and biologist Saeed Tavazoie—bring their different disciplines to bear on the effects of gene transcription and regulation. Both scientists, she says, identify fundamental problems and “take both global and quantitative approaches to studying them.” Tilghman hopes the institute will have an educational role as well, and she had recruited Harold Shapiro, Princeton's current president and chair of the U.S. National Bioethics Advisory Commission, to the faculty to cover ethics. Now she's assembling a search committee to find her successor.

Outside her field, Tilghman is known as a critic of graduate education and, in a newspaper's phrase, “a fervent advocate of women in science.” She accepts the label, but notes that she has written and talked about problems more than she has taken “concrete” actions. One of her bold proposals is that the tenure system be dropped because it is “no friend to women.” It makes huge demands at a time when women are already stressed out with young families, she asserts. She's also not impressed by the method of rating tenure candidates— counting publications. Would she scrap tenure at Princeton· “It's something that's worth looking at,” she says. “Princeton has a short tenure clock compared to other institutions, about 6 years, but there's nothing here that wouldn't benefit from scrutiny.”

As chair of a 1998 NAS study, Tilghman pushed a controversial recommendation that graduate programs in the life sciences cut back on enrollees to curb a perceived glut of biology Ph.D.s. According to Tilghman, the data showed that too many young scientists were ending up in a holding pattern, employed as cheap laboratory workers with little chance of becoming university teachers. She still feels that way. Others are uneasy with the proposal, which the NAS panel endorsed, because it raises issues that “no one wants to talk about”—proper pay for laboratory staff and how to allocate growth among competing institutions, according to one colleague. One of Tilghman's fellow NAS panel members, biologist William Brinkley of Baylor College of Medicine in Houston, Texas, has now backed away from the panel's conclusions. The economy has changed, he says, and graduates can now find good jobs in the private sector. But he admires Tilghman for her “tremendous leadership … and the way that she hasn't wavered—I respect that.”

Like many others, Brinkley also praises Tilghman as a teacher and interpreter of science: “Young people flock around her.” When she gave a talk recently at Baylor, the students “bombarded her the moment she stepped off the stage. … There wasn't that boundary that often exists between great scientists and students. They felt an identity with her.”

As president of Princeton and its chief emissary to alumni and donors, Tilghman may have to learn to “speak in generalities,” Brinkley says. But he's certain she'll do well.

14. INFECTIOUS DISEASES

# West Nile Researchers Get Ready for Round Three

1. Martin Enserink

West Nile virus, now entering its third summer in the U.S., is straining public health labs to their limits—and triggering a research renaissance

GUILDERLAND, NEW YORK—For all the misery the West Nile virus has caused since it arrived in the United States—from the cancellation of one of New York City's beloved concerts in Central Park to nine deaths—the virus has also been a source of opportunity. In this small town, 10 kilometers outside Albany in upstate New York, it has enabled virologist Laura Kramer to assemble a new research group. Although the team is still housed in a small, cramped brick building that once served as a horse stable, Kramer has been showered with money, equipment, and the possibility of hiring more people.

Kramer's group, 12 members strong and growing, is part of the Wadsworth Center, the laboratory of the New York State Department of Health. Its main—and rather tedious—task is to test thousands of bird and mosquito samples from all over the state for traces of the West Nile virus. (Just last week, neighboring New Jersey reported finding the first two dead crows infected with West Nile this summer, marking the beginning of the 2001 West Nile season.) But Kramer, who arrived here a year ago from the University of California, Davis, hopes to do her share of basic scientific research as well. “We're ambitious,” she says. “I think we've gathered an exceptional group, and we'll be able to do some very nice studies.” (The group plans to publish the harvest of the first year of research in several papers later this year.)

Kramer's lab is one of the most prominent examples of how federal and state agencies have rallied to the threat of West Nile. In New York, Governor George Pataki's administration is spending more than $20 million on surveillance, control, and research this year, while the U.S. Centers for Disease Control and Prevention (CDC) is giving the state another$3.9 million to deal with the outbreak. In a sense, the new effort marks a return to the past. In the 1960s and '70s, New York had a strong research program for mosquito- transmitted diseases, such as Eastern equine encephalitis and LaCrosse encephalitis. As those diseases waned in New York, skilled staff members retired, and more pressing public health concerns such as AIDS emerged, the program dwindled over the next 2 decades. By 1998, “the state had run the lab into the ground,” says Kramer's predecessor, Jack Woodall, who retired that year. “In the end, I had one half-time animal helper and no technicians, nothing.”

The 1999 outbreak has changed all that. “We're now seeing a renaissance, and I think that's terrific,” says Thomas Monath, a former CDC virologist and vice president at Acambis, a vaccine company in Cambridge, Massachusetts. Kramer, who spent much of her life studying a West Nile cousin called St. Louis encephalitis, “is excellent for the job,” adds Woodall, now a professor at the Federal University of Rio de Janeiro. “She knows viruses and birds, she recruited all these enthusiastic people—she's got this lab buzzing!”

Two years ago, the West Nile virus caught researchers and public health authorities completely by surprise. Never before seen in the Western Hemisphere, the virus sickened 62 mostly older people in its first year and killed seven, all of them in and around New York City. Last summer, the virus made disconcerting geographic advances, killing birds—its primary hosts—as far north as New Hampshire and as far south as North Carolina. The good news, however, was that only 21 human cases were reported, with just two fatalities. Again, most of those infected lived in New York City, although the “hot zone” had shifted from the borough of Queens to Staten Island.

This year, experts think the virus will once more rage through bird populations along the East Coast. Expect crows, by far the most susceptible species, to die in droves, they say. They also expect the virus to keep spreading, perhaps into Canada, the Midwest, and the Deep South. But the most crucial question—how many humans will get sick—is also the most difficult. “It's anybody's guess, really,” says Kramer.

Part of the problem is that viral presence in birds alone clearly doesn't signal an impending human outbreak. Researchers think that the transmission level in birds must be very high for the epidemic to spill into humans. Recently, New York State Department of Health epidemiologist Millicent Eidson found what may be a simple way to predict human risk: the “dead crow density” factor. Throughout the state, citizens were asked to report dead birds last year. Examining data from the 2000 outbreak, Eidson discovered that the number of birds reported per square mile—whether they were subsequently tested or not—was as high as 5.9 in Staten Island, where most human cases occurred. In nearby counties and boroughs, some of which had human cases in 1999 and 2000, the density was between 0.1 and 1.5, and it was below 0.1 in all other counties where no human cases occurred. This summer, Eidson says, the state health department will keep counties informed about their dead crow density to give them a rough idea of the risk for humans. Where that risk is high, cautioning the public or implementing virus control measures, such as mosquito spraying, can be considered.

## At the epidemic's epicenter

Whatever the virus's toll, the government's response is likely to be “less panicky” than in the previous 2 years, says John Roehrig, a West Nile researcher at the CDC in Fort Collins, Colorado. With help from CDC, the states with the highest level of viral activity, such as New York, New Jersey, Connecticut, and Pennsylvania, have all hired new people, spruced up their labs, and revitalized their research programs. “They're a lot more confident and a lot more capable to deal with the virus now,” says Roehrig.

Kramer, for one, is hoping that her lab will have a less frantic summer than last, when the staff was “completely overwhelmed” by the thousands of bird and mosquito samples. Many evenings and weekends were sacrificed, she says, and one technician developed severe repetitive strain injury from the endless pipetting of reagents. From a surveillance viewpoint, there's no need to test each and every bird, says Kramer, so this year, counties will be allowed to submit only two or three birds per week. The lab now also boasts a gleaming new robot to prepare the samples for testing, which should save the team hundreds of hours of work.

But time-consuming as they are, the tests give Kramer's lab one great advantage over most others: unparalleled access to samples from across the epidemic's epicenter, which will help provide data for a broad array of studies. Researchers still don't know, for instance, how the virus survives the harsh Northeastern winters, exactly what roles different mosquito and bird species play in its transmission, why it kills crows en masse, or how it will evolve as it spends more time in North America. Kramer's group plans to study all those issues, in addition to looking for possible drugs that could battle the infection in humans. “They're gonna come up with a lot of interesting stuff,” Woodall predicts.

Yet Kramer and others wonder how much longer the federal and state governments will be willing to spend big bucks on the virus. With just a few dozen cases a year, West Nile is still an exceedingly rare disease. To hedge her bets, Kramer plans to tap other sources of funding, such as grants from the National Institutes of Health. But even if West Nile virus never becomes a big public health threat, she says, the money was well spent: Revamping the crumbling public health infrastructure will eventually pay off, she predicts, as other exotic pathogens are sure to arrive. “Tremendous amounts of money have been spent on West Nile,” she concedes. “It may look like a windfall, but it was sorely needed.”

15. MINORITY FACULTY

# New Data in Chemistry Show 'Zero' Diversity

1. Jeffrey Mervis

A recent survey of major U.S. chemistry departments reveals that there are even fewer minorities on the faculty than anyone suspected

The number of chemistry Ph.D.s awarded to blacks each year in the United States has more than doubled since Delroy Baugh received his degree in 1990. Yet the number of blacks hired as assistant professors at the nation's top 50 chemistry departments has held steady—at zero—since Baugh took an entry-level faculty post in 1991 at the University of California, Los Angeles (UCLA).

View this table:

That finding shocked Donna Nelson, an associate professor of chemistry at the University of Oklahoma, Norman, who asked the 50 chemistry departments carrying out the most research for the ethnic and gender composition of their faculty members. She and her students found that African Americans/blacks or Hispanics constitute barely 1% of the 1637 tenured or tenure-track faculty members at the top 50 schools, and that 23 of the 50 departments have none (see table). They also learned that 12 of the 18 blacks (13 are African Americans; the rest earned undergraduate degrees from other countries) are full professors at or near retirement age, and that none is an assistant professor. “I was stunned,” says Baugh after learning that he was, at age 41, probably the youngest tenured black chemistry faculty member among the most research-intensive departments. “I knew the number [of assistant professors] was small. But I didn't realize it was zero.”

A Native American who grew up in Oklahoma, Nelson began with the idea of surveying female minority faculty members in chemistry. “But I gave up on that pretty soon,” she says. After counting herself, “it was months before I found another.” The minuscule numbers—she eventually identified seven at the 50 institutions—led her to cast a wider net. But the totals in other categories were equally depressing. To Nelson, the numbers suggest that the continuing flow of reports about the importance of diversity in academia (Science, 21 July 2000, p. 378) hasn't reached the people who actually do the hiring.

With no data available on the actual number of hires in the past decade, the chairs of some top-ranked departments insist that the real problem is the tiny numbers of chemistry Ph.D.s awarded to underrepresented minorities: 56 blacks and 42 Hispanics in 1999. The numbers represent only 4% and 3%, respectively, of the 1400 chemistry Ph.D.s produced that year. “We are constantly on the lookout for such people,” says Stephen Lippard, head of the chemistry department at the Massachusetts Institute of Technology (MIT), whose 29-member department has two Asians (who are not an underrepresented minority in science) but no African Americans or Hispanics. “But the pool is a lot smaller than we'd like.” In addition, many minority chemists go to work for industry, and others choose historically black colleges or institutions that emphasize undergraduate teaching.

James Anderson, chair of the division of chemistry at Harvard University, which has four Asians and no underrepresented minorities, says that faculty searches at his university are color-blind: “We have found that excellence doesn't have anything to do with ethnic categories or gender.” Still, he confesses that “I didn't realize that it was so bad.”

But some observers say that a scarcity of candidates, a phenomenon true for other disciplines in the physical sciences, doesn't fully account for the problem. They also point to a chilly climate in many chemistry departments that discourages young scientists. “I think that there is a push away from universities as well as a pull by industry,” says chemist Marge Cavanaugh, who has been involved in several efforts sponsored by the National Science Foundation to bolster underrepresented minorities. The negative attitudes are reflected in several questionable practices, say minority faculty members, including a failure to interview qualified minority candidates, loading down a new faculty member with introductory courses, and marginalizing senior scientists. The combination of shabby treatment and small numbers, they believe, leads to a perpetuation of the status quo.

“My honest feeling is that nobody cares,” says Philip Phillips, a West Indian trained as a theoretical chemist who spent 9 years at MIT. He left in 1993 for a tenured position in the physics department at the University of Illinois, Urbana-Champaign, which last year promoted him to full professor in its top-rated solid state physics program. “People think that the situation will improve if there are more minority Ph.D.s,” says Phillips. “That's important, but there also has to be active involvement and a commitment to the cause. And I don't see that.”

Baugh, who was born in Jamaica and came to the United States as a teenager, is used to being a racial exception in professional situations. Although Baugh says he faces no “day-to-day problems” relating to race, “I'm almost always the only black, especially at selective meetings like a Gordon conference.” He says that in his 10 years at UCLA—its 51 tenured and tenure-track faculty members make it one of the largest chemistry departments in the country —“I can't remember ever interviewing any [underrepresented] minorities” for faculty slots.

His path to tenure may also have been colored by his ethnicity, he says. “Before I got tenure [in 1997], I taught a freshman course every year. I found out later that no other young faculty member, before or since, had done that.” He speculates that the heavy teaching burden he was assigned may have been a well-meaning attempt to attract minority undergraduates to the department. “But it put me at a big disadvantage when I came up for tenure.”

Gregory Robinson, 42, already was a full professor at Clemson University in South Carolina (outside the top 50) when he took a step up in 1995 and joined the chemistry faculty at the University of Georgia, Athens. “There's a feeling of despair,” he says, among some of his minority colleagues. “Affirmative action has become a bad word, and a diverse faculty is not a priority anymore. I was the first African American in the chemistry department at both Clemson and Georgia, and even today, there's a good chance that a minority hired by any institution will be the first one.”

Robinson, who grew up in Alabama, admits that “chemistry is a tough row to hoe” and that the life of a science faculty member at a major research university is stressful. But he bristles at the notion that African-American chemistry Ph.D.s “collectively and en masse decided that they do not want positions at these institutions.” Instead, he says, there's a lack of concern about the value of a diverse faculty; he has experienced it personally. Despite a flourishing lab, major federal grants, and frequent media coverage of his research on multiple metallic bonds, Robinson says that he never even got a response to job queries that he sent in recent years to several top programs, much less an interview. Even in a tight academic market, he says that the silence was surprising.

Such experiences breed a sense of distrust of academia among minority Ph.D.s weighing their career options, says Billy Joe Evans, an African-American professor of chemistry at the University of Michigan, Ann Arbor, who, at age 58, says he is fighting efforts to force him out after 31 years. “A lot choose industry not for the money,” he says, “but because the workplace is cut and dried. The bottom line is clear, and hard work is rewarded.” That's not always the case in academia, notes Evans.

University of Washington, Seattle, chemist John Macklin, 61, says that a similar campaign by the university to oust him has finally succeeded. “It's a very lonely place,” says Macklin about his 33-year career on a faculty that, with three blacks and one Hispanic, is currently more racially diverse than any other top-50 department in the country. He says he's agreed to give up his lab and retire in a few years in exchange for a significant hike in his salary, now the lowest in the department.

The combination of retirements and a dearth of new blood will further erode the status of minority chemistry faculty members in the next several years unless something dramatic is done, predict Nelson and others. Harvard's Anderson says that's exactly the goal of a new effort that tackles one subset of the underrepresented population—women. “We are going after women with a vengeance,” he says, noting that the department's current gender distribution “is completely unacceptable. … We realized that the university needs to become a promoter, mentor, and cheerleader for these young faculty [members].”

Although many ethnic minority scientists support such efforts, some feel that they are once again being asked to wait their turn. “Women are half the population, and they have a significant political voice,” says Phillips. “That's not the case for minorities. And the idea that we might be wasting a valuable resource just isn't a very compelling argument anymore. There's a live-and-let-live attitude in academia and no structure in place to improve things.”

16. PALEOCLIMATE

# A Variable Sun and the Maya Collapse

1. Richard A. Kerr

A record of drought from the bottom of Yucatán lakes suggests that an inconstant sun may have helped drag down the mighty Maya

Tackling a touchy question outside the mainstream of opinion usually gives a scientist pause. But on page 1367 of this issue paleoclimatologist David Hodell and his colleagues take on two touchy subjects at once. They argue that subtle variations in the sun's brightness helped trigger a drastic climate change, and that, in turn, played a role in the downfall of a whole civilization. Drawing on a mucky lake-bottom core from the Yucatán Peninsula, home to ancient Mayas, they confirm that the area's worst drought in many millennia struck just as Maya civilization began its accelerating decline. That drought was only one of many that tended to return every 200 years, in step with and presumably driven by 200-year oscillations in solar activity.

Mayanists are guardedly receptive of the climate-culture connection. The evidence for a major drought “seems pretty compelling,” says archaeologist Takeshi Inomata of the University of Arizona in Tucson. “It's quite possible it was a major factor, but I don't think climate itself is the sole factor of Maya collapse.” Paleoclimatologists are perhaps more enthusiastic about the sun-climate connection. “The Hodell result adds to a string of recent papers that document the importance of solar variability for climate change,” e-mails paleoceanographer Peter deMenocal of Lamont-Doherty Earth Observatory in Palisades, New York, from his research ship exiting the Suez Canal. Tightening such sun-climate-culture connections will take more mucking about in Maya country.

The new record of Maya climate is actually an improved version of one that Hodell, who works at the University of Florida, Gainesville, analyzed in 1995. The new 1.9-meter core came from a different part of Lake Chichancanab in the central Yucatán, a spot where sediment accumulated more rapidly. That allowed analyses as frequent as every 6 or 7 years along the 2600-year-long core. And a greater number of samples of organic matter could be dated by accelerator mass spectrometry, improving dating. All in all, Hodell extracted a more detailed, more accurately timed chronology of drought in the vicinity of the lake than before, principally through measurements of the varying amount of gypsum—calcium sulfate—deposited on the lake floor. Whenever rainfall decreased, evaporation from the lake would concentrate salts in the lake water and begin precipitation of gypsum.

The new Lake Chichancanab drought record shows just how hard times were for the Maya at the end of their heyday. Droughts of varying intensity and duration pepper the 2600-year record, but its most intense, most prolonged drought runs from about A.D. 750 to 850. In fact, this was the region's worst drought in 7000 years, according to a longer, less detailed record of Hodell's from the same lake. And the megadrought came just as Maya civilization entered its decline, which ran from about A.D. 750 to 900. The decline was measured by the number of sites where people were building the massive temples and stone monuments that typify the Maya Classic Period. “It's hard for me to believe that's just a coincidence,” says Hodell. “I think drought did play an important role, but I'm sure there were other factors, such as increasing population, degradation of the land, and sociopolitical change, that interacted. Civilization collapse has got to be complex.”

However complex the collapse, its timing may have been a simpler matter to explain. The well-dated, high-resolution Chichancanab record allowed a comparison with solar activity over the same period. In the lake record, drought had a tendency to recur every 208 years on average. Solar activity—including varying sunspot numbers and the brightness of the sun—is recorded in the abundance of cosmic ray-produced radioactive carbon-14 preserved in tree rings. Solar activity also varies in a “bicentennial oscillation” with a period variously reported to be between 206 and 208 years. Comparing records, Hodell found that the bicentennial oscillations in each were in step throughout. Solar variations, therefore, could have triggered the recurring drought, he speculates, conceding that “there have to be other factors involved” to account for the varying intensity of recurring drought.

As might be expected, reaction to the sun-climate-culture connection varies with the specialty. Archaeologists express concerns about how paleoclimatologists view the archaeology, emphasizing that cultural evolution is more complex than talk about a “collapse” might suggest. Rather than a sudden downturn from one end of the Maya homeland to the other, they say, the collapse began in the wetter southern highlands of Guatemala around A.D. 750. At the same time, the drought was settling over the typically drier northern Yucatán lowlands even as civilization there flourished. Only 100 years later did Classic Maya culture succumb in the drier north. “The biggest problem,” says archaeologist Matt E. O'Mansky of Vanderbilt University in Nashville, Tennessee, “is why, in a drought, does the dry area last longer than the wet area·” Physical geographer Timothy Beach of Georgetown University in Washington, D.C., allows that the drought is real enough, and “some people would say it's part of the mix of causes for the collapse.”

Paleoclimatologists are loath to meddle in matters of archaeology, but many of them are impressed by the sun-climate connection supported by the Chichancanab record. Given that the drought and solar cycles are in step, “they've made the case as far as I'm concerned,” says statistical climatologist Michael Mann of the University of Virginia in Charlottesville. Coincidentally, environmental physicist Ulrich Neff of the Heidelberg Academy of Sciences in Germany and his colleagues make the same case in this week's issue of Nature using a climate record of the Indian Ocean monsoon preserved in a stalagmite from a cave in Oman. They too find a bicentennial climate signal in step with the tree-ring record of solar activity. No cultures collapsed there, but the meteorological setting is much the same as in Mesoamerica. That should go some ways toward making sun-climate a less touchy subject.