# News this Week

Science  10 Nov 2000:
Vol. 290, Issue 5494, pp. 1062
1. GENETIC TESTING

# Families Sue Hospital, Scientist for Control of Canavan Gene

1. Eliot Marshall

A successful partnership between parents and a scientist to combat a deadly genetic disease has dissolved into a bitter legal battle over the commercial tests used to identify people with dangerous mutations in their genes. The lawsuit, filed on 30 October in Chicago federal court, is the latest dispute in the growing controversy over who controls and who benefits from human genetics research.

Thirteen years ago, the father of two children suffering from Canavan disease—a fatal illness whose symptoms begin appearing 3 months after birth—approached a scientist named Reuben Matalon and persuaded him to begin developing molecular probes to trace the disease to its source. They also set up a registry of families and helped recruit tissue donors. The disease, which affects 1 in 6400 Ashkenazi Jewish children, is caused by a mutation on chromosome 17 that leads to a deficiency of the enzyme aspartoacylase, gradually destroying the central nervous system. With the families' support, Matalon found a Canavan gene in 1993 and developed a genetic test. Matalon's employer at the time, Miami Children's Hospital (MCH), obtained a patent on the gene in 1997, and the next year began licensing a test that could identify lethal Canavan mutations.

The terms of that license are the focus of the suit, filed by four parents and three nonprofit groups. They charge that Matalon and MCH are guilty of “misappropriation of trade secrets” based on their use of the children's blood and tissue, without consent, to secure a gene patent and develop a commercial test. Laurie Rosenow, an attorney at the Chicago-Kent College of Law in Chicago, Illinois, who helped prepare the complaint, says that this is the first time tissue donors have taken researchers to court for control of a gene. “It's a unique case” that could shape future genetic research partnerships, she adds.

Other patient groups are trying to head off such clashes by working out legal agreements in advance. For example, a support group for families with pseudoxanthoma elasticum (PXE), an inherited disease that causes calcification of connective tissue, has been negotiating the terms of tissue donation with researchers since a gene was discovered in February. Sharon Terry, president of PXE International in Sharon, Massachusetts, hopes to sign an agreement soon with the gene discoverers and their employer, the University of Hawaii, to share control of patents. The support group has promised to pick up the patent application costs.

But there was no such agreement to clarify the roles of researchers and tissue donors when Daniel Greenberg, father of a child with Canavan disease, visited Matalon in 1987 to propose a collaboration. Greenberg heads the list of plaintiffs in the Canavan suit, which includes the Canavan Foundation of New York City, Dor Yeshorim of Brooklyn, New York, and the National Tay-Sachs & Allied Diseases Association Inc. of Brighton, Massachusetts. The suit seeks to block MCH's commercial use of the Canavan gene and recover damages of more than $75,000 derived from royalties collected on the Canavan test. The plaintiffs object to the$12.50 royalty fee MCH is charging. In addition, according to the complaint, they claim that MCH has tried to restrict access and promote a lead test center by setting a limit on the number of tests that can be performed by each licensee. The Canavan Foundation was forced to stop offering free genetic screening, according to the complaint, after being advised that it would have to pay royalties and comply with other licensing terms.

Matalon, who now works at the University of Texas, Galveston, says he has no stake in the dispute. “I get no royalties, no benefit from it,” he says. “My interests have nothing to do with patents.”

Matalon acknowledges that the Canavan parents helped him to get started by contributing tissue and “seed money” amounting to no more than $100,000. But MCH provided$1 million a year, he says, and in return asked him to turn over any marketable intellectual property. “They say, ‘Let us know [about discoveries], and we will decide about the patent.’”

The parents' complaint includes a copy of a 12 November 1998 letter from MCH's chief financial officer, David Carroll, to a clinic testing for Canavan disease. Noting that users of the test must obtain a license from MCH, Carroll wrote, “We intend to enforce vigorously our intellectual property rights relating to carrier, pregnancy, and patient DNA tests.”

MCH spokesperson Cynthia Gutierrez declined to discuss the case, citing the ongoing litigation. The Canavan parents also have decided not to comment.

The suit highlights the key role that families can play in helping scientists with their research. Judith Tsipis, a biologist and genetic counselor at Brandeis University in Waltham, Massachusetts, who lost a son to Canavan disease, notes that the Canavan families identified families at risk and collected tissues. The legal battle, she insists, “is not about the Canavan families wanting a piece of the pie,” but about having a say in how their contributions are used.

2. CLINICAL TRIALS

# Company, Researchers Battle Over Data Access

1. Carol Cruzan Morton*
1. Carol Cruzan Morton is a writer in Watertown, Massachusetts.

A dispute between university-based researchers and the corporation that funded their study is threatening to erupt into a $7 million to$10 million legal battle. Last week, the researchers reported that a large clinical trial of an immune system booster to treat HIV-infected people found that the drug isn't effective in slowing progression to AIDS or reducing mortality. The company that developed the drug tried to block publication of the study unless the researchers included the company's analysis of a subset of the data that suggests the drug might help some people. The researchers refused.

This nasty dispute has again raised the issue of who controls the data when corporate and academic interests conflict. “This is probably the unusual case, where investigators and the journal are standing up to the supporting companies,” says science policy analyst Sheldon Krimsky of Tufts University in Medford, Massachusetts. “More typically, you find investigators willing to compromise to avoid legal action or loss of funding for future projects.”

The study is believed to be the largest randomized clinical trial among HIV-infected persons in the last decade. The 3-year, double-blind study of 2527 otherwise healthy HIV-positive people at 77 U.S. sites tested a drug called Remune, developed by Immune Response Corp. of Carlsbad, California. Immune Response and the University of California, San Francisco (UCSF), Center for AIDS Research funded the research.

The trial ended in May 1999 when an independent safety monitoring board decided that the drug showed no clinical benefit and was unlikely to do so. That's when trouble started brewing, says AIDS researcher James Kahn of UCSF, the study's national principal investigator. In the news release announcing the trial's early end, Immune Response claimed that an analysis of a subset of people who underwent more frequent blood tests indicates that Remune reduced the amount of HIV in their blood—the “viral load.” This effect, the company noted, would be the basis of its application to the U.S. Food and Drug Administration for marketing approval for the immunogen. (Another trial, focusing on the drug's effect on viral load, began in September 1999.) Kahn and the study leadership team conducted a preliminary analysis of a larger sample, which they presented at a fall meeting in San Francisco. Remune, they concluded, had no apparent clinical effect and no discernible effect on viral load.

In January, the disagreement about how to summarize the virologic effects led the company to propose that Kahn, biostatistician Stephen Lagakos of the Harvard School of Public Health in Boston, and two other researchers could have access to the complete data set—which the company controlled—if they agreed to written company approval of “the content, analysis, results and discussion” before publication, according to a memo from the company to Kahn and his team. The memo also asked for prior approval of any further analysis and to limit the researchers' access to the data to 1 year. “We were flabbergasted that they would put new conditions on getting the data, and we objected strenuously,” Kahn says.

The researchers didn't accept the terms. Instead, they used the data submitted to the safety board, which they say is 95% of the results on clinical progression. This summer, they sent both a draft and then the final manuscript to Immune Response for review to ensure that it contains no proprietary information, as required by their contract. The researchers incorporated some revisions, but refused to add a figure illustrating the company's analysis of the subset data.

Ronald Moss, Immune Response's vice president for medical and scientific affairs, says that “despite the failure to show significant differences in clinical endpoints, [the company's subset analysis] gave us valuable insight into the potential effects of Remune on viral load and T cell help. … The Remune group is favored at weeks 36, 48, 60, 84, 96, and 120 … we felt it was extremely important to have a section in the paper describing and discussing the results.” Lagakos counters, however, that he also analyzed the data for the subset, and “there were no significant differences using the analytical methods specified in the protocol.” Kahn adds: “Immune Response used a statistical test that was inappropriate for the data. The company thinks ‘data dredging’ makes sense. There are no differences at certain interim time points, and there are differences at others. One cannot pick and choose data points to suit one's needs.”

When it was clear that they would not reach agreement, Immune Response invoked a contract clause asking for legally binding arbitration, seeking damages of $7 million to$10 million. The company claims that the research agreement gives the researchers access only to data generated by the UCSF site, and that data from other sites are confidential. UC has filed a counterclaim asking for the complete data set and maintaining the right to publish further analyses. “In every one of three key documents—the research agreement, the protocol, and the site agreement—there is very clear language that the study team will publish the results of the study and that they have the right to do that,” says UC counsel Christopher Patti.

The researchers submitted their manuscript in September to the Journal of the American Medical Association, which quickly published the paper in the 1 November issue along with a cluster of articles and a commentary that address academic conflicts of interest with industry research sponsors.

The controversy has sparked curiosity about the company's version of the subset analysis. Alexandra Levine of the University of Southern California in Los Angeles says that the researchers should have included the company's data. “Why not give the reading audience full access to the data?” she says. “If the authors are presenting data fairly, then present all of it.”

Moss says the full story will be out soon; other investigators involved in the clinical trial will publish another analysis, with the disputed figure, possibly in January.

3. EVOLUTIONARY BIOLOGY

# Twinned Genes Live Life in the Fast Lane

1. Elizabeth Pennisi

The financial rewards of genome sequencing may go to the companies, but the intellectual fruits of this multimillion-dollar enterprise are going to the likes of evolutionary biologist Mike Lynch and computer scientist John Conery. On page 1151, this duo at the University of Oregon, Eugene, describes new insights into how genes arise and fuel evolution. By trolling through sequence data for nine very distinct organisms, they have uncovered evidence that genes are copied far more frequently—and the duplicates are lost from the genome far faster—than researchers had thought. What's more, the work suggests that some duplicate genes play a key role in the evolution of new traits and in speciation. Although some researchers question the Oregon team's conclusions, the report is nevertheless “a very nice example of how the creative analyses of genomic databases can provide valuable but previously inaccessible information about evolution,” says Loren Rieseberg, an evolutionary biologist at Indiana University, Bloomington.

More than 30 years ago, geneticist Susumo Ohno of the City of Hope Hospital in Los Angeles proposed that genomes grow and diversify by gene duplication, an idea that most evolutionary biologists have since come to accept. It seems that when—by some quirk of DNA replication—a gene, piece of a chromosome, or whole genome is copied twice, the “extra” genes can take on a new function and expand the organism's genetic repertoire. This extra copy might become active at a different time in development or in a different tissue, or it may undergo base changes that alter the properties of the protein encoded by that gene. Yet until recently, researchers had no good way to determine whether Ohno was right. “They have had only a few duplicates” with which to try to estimate the life-spans of twinned genes, explains Andreas Wagner, an evolutionary biologist at the University of New Mexico, Albuquerque, and the Santa Fe Institute.

But thanks to the recent flurry of genome sequencing—the genomes of the fruit fly, yeast, and nematode are virtually complete, and others are close behind—Lynch and Conery were able to get a more comprehensive view of the potential of duplicate genes for furthering evolution. To do so, Lynch and Conery used a computer program to find duplicate genes in the three completed genome sequences and among all the protein-coding sequences available for the mouse, chicken, human, rice, and the plant Arabidopsis thaliana.

The researchers relied on sequence differences in the matched copies to estimate the age of each copy, as differences accumulate through time. Specifically, they counted the number of silent nucleotide base changes—those that didn't alter the protein code—to date the duplication event. Then they compared the number of silent changes to the number of base changes that caused protein alterations. This ratio told them whether the copy was changing faster or slower than expected.

Lynch and Conery found that most of the duplicated genes are relatively young and that extra genes disappear quickly, at least on an evolutionary time scale. In the human and mouse, for example, about half of new copies disappear within 7.3 million years.

Perhaps most surprising, the two found an “astronomical rate of gene duplication,” says Sally Otto, an evolutionary biologist at the University of British Columbia in Vancouver, Canada. In fact, duplications occur as often as single-base changes within genes, which have long been considered the primary means by which genomes evolve. The rates are similar among such disparate organisms as fruit fly and yeast, notes Lynch; a genome with 15,000 genes could acquire between 60 and 600 duplicate genes over a million years as fodder for speciation. “Gene duplications are so frequent that we really need to take them into account as an important source of genetic variation,” says Wagner.

Nor do genes need to morph much before they begin to divide one species into two, Lynch suggests. For example, if a population carrying a recently twinned gene splits up, there's a good chance that the fates of the “extra” copies in the two resulting groups will diverge. In one group, one copy might jump to a new chromosome, while in the other, the copy might move to a different spot in the genome. If the populations merge again, these gene shifts will have made their genomes incompatible. Individuals from the two groups could still mate, but this incompatibility would likely make their offspring less fit.

But several researchers question how Lynch and Conery came up with their duplicate genes and worry about some of the resulting estimates. Manyuan Long, an evolutionary biologist at the University of Chicago, thinks that their analysis doesn't adequately take into account the long-lived gene copies, many of which also exist in these genomes.

Even if the estimates are rough, counters Wagner, “for my work, they are very, very relevant.” And he expects that others will take these results as starting points for their own work: “We can plug these estimates into models [to study] the evolution of many interesting things.”

4. THEORETICAL PHYSICS

# Offbeat Lenses Promise Perfect Fidelity

1. Charles Seife

A battleship spied by periscope, a kestrel watched with binoculars, a nebula under the Hubble Space Telescope's gaze: What do these images have in common? None faithfully represents the real thing. A seemingly ineluctable property of any lens is that it cannot focus all wavelengths of light shed by a distant object. What's viewed, therefore, is to some degree a washed out, grainy version of the original. But now a British physicist has found an ingenious solution that lights the way to building a perfect “superlens.” That notion has set other experts abuzz. “This is kind of amazing,” says Eli Yablonovitch, a physicist at the University of California (UC), Los Angeles. “It's a real theoretical breakthrough.”

Most of the time, light travels in an arrow-straight line. But when a beam passes from one material into another, its speed changes, causing it to veer in a slightly different direction. The amount of bending depends on the refractive indexes of the two materials—roughly speaking, measures of light's speed in those materials. By shaping a lens just right, opticians can exploit this bending to make rays converge at a point beyond the lens. But even the best conventional lenses are unable to focus all the light rays; some wavelengths are inevitably lost.

Some deft calculations, however, point to the surprising conclusion that it doesn't have to be that way. Physicist John Pendry of Imperial College, London, used Maxwell's equations—the basic laws governing electromagnetic waves—to examine the behavior of individual wavelengths of light as they pass through a lens. A distant object is blurry because various wavelengths get out of step, like a collection of metronomes, once in sync, that start beating at different tempos. “The function of the lens is to correct that phase difference,” says Pendry. It's as if the lens selectively slows each metronome so that the assembly can again sound off in lockstep: When the metronomes synchronize, the image comes into focus. But not all wavelengths can be salvaged. According to the equations, some waves evanesce before reaching the focal point. That means the reconstructed image is missing some of the reflection's original components. Even with the best lens, details are lost.

But Pendry discovered a loophole in the equations. His insight was inspired by work described at a meeting of the American Physical Society last March by Sheldon Schultz and colleagues at UC San Diego. Most materials have a positive refractive index; the bigger the index, the slower light moves. The refractive index of air, for example, is 1; that of water, 1.33. Schultz's group found a way to make a material with a negative refractive index—one in which light bends in the opposite direction from the way it bends on entering a glass lens.

Pendry calculated that evanescent waves are not lost when passing through a hypothetical material with a refractive index of −1. “It's a very strange property,” he says. “The slab of material grabs hold of the evanescent waves and removes their decay” by shoring up the waves. “It is almost as if it acts as an amplifier,” adds Yablonovitch. “It's a feat that is hard to believe.” As a result, all the light waves passing through a negative refractive lens reach the focal point intact, preventing any loss of resolution and creating an image that perfectly duplicates the original. Pendry's calculations appear in the 30 October Physical Review Letters.

More conventional materials might also make perfect lenses if other electromagnetic properties of theirs were tuned just right, Pendry says. He thinks a very thin film of silver could do the trick. But whatever its composition, a superlens would have drawbacks. For instance, to capture evanescent waves, the lens must be placed only nanometers away from the object being observed and would focus the image roughly the same distance from the lens. That scale isn't useful for naval warfare or bird-watching—let alone astronomy—but Pendry hopes that tiny superlenses will find uses in such pursuits as lithography and medical imaging.

5. CELL BIOLOGY

# New Clues to How Genes Are Controlled

1. Jean Marx

The transformation of a single cell into a complex organism requires an exact system for regulating gene expression. It wouldn't do, say, to have hormone-secreting cells make liver proteins, or even the wrong hormone. Cell biologists don't know exactly how developing cells achieve this precision, but they do know it involves so-called transcription factors—proteins that can turn genes on or off. Now, researchers have intriguing new information about how the transcription factor called Pit-1 works.

Pit-1 is needed to activate the genes for three hormones—growth hormone, prolactin, and thyrotropin—each of which is made by a different type of cell in the pituitary gland. But how Pit-1 turns on the right gene in each cell type without activating the other two has been a mystery. Work described on page 1127 by Kathleen Scully and Michael G. Rosenfeld of the University of California, San Diego, and Aneel Aggarwal of Mount Sinai School of Medicine in New York City and their colleagues points to an answer.

To exert its effects, Pit-1, like other transcription factors, has to bind to a regulatory sequence on its target genes. The Rosenfeld-Aggarwal team has shown that a small sequence variation between the regulatory elements of the prolactin and growth-hormone genes causes Pit-1 to bind very differently to the two. As a result, when Pit-1 binds to the regulatory region of the growth-hormone gene in prolactin-producing cells, it apparently attracts proteins that suppress the gene's activity, whereas on the prolactin gene it attracts activating coregulators. “They're basically arguing that a given regulatory factor can act as a switch, in some cases causing activation and in others repression,” says developmental biologist Michael Levine of the University of California, Berkeley (UCB).

It's not unusual for transcription factors to have dual functions, but until now Pit-1 was thought to be an activator only. Beyond that, the finding supports the idea that the sequences that bind transcription factors are more than just docking sites. Instead, as work with another set of transcription factors, the so-called nuclear receptors, has already shown, small changes in these sequences can influence the three-dimensional structure of the bound factor. And that structural change can in turn influence which other proteins bind to the transcription factor on the regulatory site—and ultimately, whether genes are turned on or off. “The information is in the primary DNA sequence, as Watson and Crick told us,” Rosenfeld says.

The Rosenfeld team started their experiments by asking what role Pit-1 binding sites might play in selective expression of a target gene. To find out, Scully introduced two genes separately into mice: one with the normal regulatory region for growth hormone and one in which the Pit-1 binding regions were replaced by a comparable element from the prolactin gene.

As expected, the gene with the normal regulatory element was expressed only in the growth hormone-producing cells (somatotropes) in the animals' pituitaries. But the gene with the mutant sequences was expressed in both the growth hormone- and prolactin-producing cells (lactotropes). These results indicate that Pit-1, when bound to the normal growth- hormone sequence, somehow keeps the gene “off” in the prolactin-producing cells while allowing it to be “on” in the growth-hormone cells. Indeed, cell biologist Keith Yamamoto, also of UCB, notes that the Rosenfeld team's results imply that gene repression is Pit-1's default activity. That finding, he says, “is a real surprise,” and suggests that “the growth hormone and prolactin elements evoke distinct configurations of Pit-1 that somehow produce distinct patterns of activity.”

X-ray crystallographic studies performed by Aggarwal and his Mount Sinai colleague Eric Jacobsen in collaboration with the Rosenfeld group support that idea. They showed, for example, that two of the protein's characteristic regions, or “domains,” end up on perpendicular faces of the DNA of the prolactin element but are on the same face of the DNA of the growth-hormone sequence. This difference can be traced to the presence of two extra bases in the Pit-1 binding site of the growth-hormone gene. Further work indicates that the shape change induced in Pit-1 by this difference enables it to recruit repressive proteins to the growth-hormone gene.

These results help explain why growth hormone is “off” in lactotropes; what is still unclear is how the gene is turned on in somatotropes. “That's the crucial question,” Rosenfeld says. “You have to have an override mechanism” to eliminate the repressive effects of the gene's regulatory sequences.

Despite the unanswered questions, Levine is impressed that the team has gone so far—“from transgenic animals to crystallography”—in explaining the cell specificity of Pit-1's effects. Given that a similar mechanism has already been found by Yamamoto and others for nuclear receptors, which regulate gene expression in response to steroid hormones and retinoids, Levine suspects it may be widespread: “You can envision many proteins where this can happen.”

6. NEUROSCIENCE

# Pesticide Causes Parkinson's in Rats

1. Laura Helmuth

A widely used pesticide causes a syndrome in rats that looks, both behaviorally and neurologically, very much like Parkinson's disease. This new finding supports tentative epidemiological data suggesting that pesticide exposure increases a person's risk of developing the disease, which afflicts about 1 million people in the United States and is characterized by tremors, slowness, and a loss of balance. It also gives Parkinson's researchers their best model system yet for investigating how and why the disease strikes.

Although the research team, led by Timothy Greenamyre of Emory University in Atlanta, was intrigued by the epidemiologic clues, the study was designed instead to answer fundamental questions about the disease. They used the pesticide rotenonethe active ingredient in hundreds of products, from flea and tick powders to tomato spraysbecause its structure and mode of action resemble those of a compound called MPTP. In the early 1980s, MPTP was found to cause a severe Parkinson's-like syndrome in young heroin addicts.

Researchers quickly figured out what had happened to the addicts: MPTP is metabolized to MPP+, which slips through the blood-brain barrier. Most neurons ignore the metabolite, but those carrying receptors for the neurotransmitter dopamine suck it up. Once inside these neurons, MPP+ interferes with electron transport in the cells' mitochondria, releasing free radicals that eventually kill the cells. This produces the same movement defects as those seen in Parkinson's disease, which is caused by the loss of dopamine-producing neurons in a brain region called the substantia nigra.

One of the more chilling aspects of the MPTP episode was the realization that many common pesticides are structurally similar to MPP+. What's more, both rotenone and MPP+ kill cells by interfering with part of the mitochondria's electron transport system called complex 1. Now, as described this week at the Society for Neuroscience meeting in New Orleans, Greenamyre's team has shown that rotenone produces Parkinson's-like symptoms in rats similar to those MPTP induced in humans. (The results will also appear in the December issue of Nature Neuroscience.) “I've been hoping someone would do the work that Tim is publishing,” says neurologist Caroline Tanner of the Parkinson's Institute in Sunnyvale, California.

In the experiment, 25 rats injected with the pesticide for 1 to 5 weeks developed rigidity and unsteady movements. In the rat's brains, the dopamine-producing circuits deteriorated, and surviving cells had cellular deposits that looked a lot like Lewy bodies, another hallmark of Parkinson's. Other animal models mimic the dopamine circuit degeneration of the disease, but this is the first to show Lewy body-like deposits as well, making this an excellent model of Parkinson's, says Virginia Lee, a neuroscientist at the University of Pennsylvania in Philadelphia.

The researchers chose rotenone as a possible trigger of a Parkinson's-like syndrome to test the importance of one subtle symptom of the disease. In the last decade, other teams had found that mitochondrial complex 1 action is disrupted throughout the bodies of patients with Parkinson'sin blood cells and muscle cells, as well as in the dopaminergic circuits. No one knew how important this systematic complex 1 inhibition was. Could interfering with complex 1 throughout the bodynot just in the dopaminergic cells that MPP+ infiltratescause the disease?

In Greenamyre's rats, at least, disrupting complex 1 systematically can produce what looks like Parkinson's disease. Rotenone, unlike MPP+, can slip through any cell's membranes. The researchers found that, as expected, complex 1 activity was inhibited throughout the brain, but only the dopaminergic cells degenerated, just as in Parkinson's. Lee suspects that dopaminergic neurons are more fragile than other cells and can't withstand the free radical damage caused by rotenone's disruption of complex 1.

As to whether rotenone or other pesticides contribute to Parkinson's in humans, the researchers urge caution. So far, more than 15 epidemiologic studies have linked Parkinson's to crude environmental risk factors, such as living in the countryside or working in the agricultural, chemical, or pharmaceutical industries. But no single chemical, including rotenone, has been reliably implicated as a risk factor. At this stage, Greenamyre suspects the risk of Parkinson's is a function of genetic predispositionpotentially related to how efficiently one metabolizes toxins—as well as of environmental exposures.

7. SCIENCE EDUCATION

# Ehlers Bill Suffers Surprising Defeat

1. Jeffrey Mervis

A popular, bipartisan bill to improve school science and math education derailed suddenly in Congress late last month after critics said that it might violate a constitutional ban on government support for religion. But the action involved more than scholarly debate. The House's 24 October vote also demonstrated the political clout of the country's two major teachers' unions—which disapproved of a provision for grants to private schools—and the relative weakness of scientific groups that lobbied for the bill.

Likewise, Los Alamos managers take issue with an analysis by Chen that shows a $3000-a-year average salary gap between Asian Americans and their Los Alamos colleagues. “The lab found a statistically insignificant difference in salaries between the two groups,” says Jacqueline Paris-Chitanvis, a lab spokesperson. But Los Alamos officials, like their Livermore colleagues, say they cannot release their data. ## Catalyst for action It took the Lee case to bring these issues of pay and the glass ceiling out in the open. Lee's treatment, and the harsh lab security measures imposed in the wake of his March 1999 firing, prompted two organizations—the Asian Pacific Americans in Higher Education and the Association of Asian-American Studies—to call for an employment boycott of all DOE labs. Asian Americans, however, are sharply divided over whether a boycott is the proper approach. “It is hurting the labs and creating a wall at a time when we need dialogue,” says Manvendra Dubey, a Los Alamos atmospheric chemist and chair of the Asian-American diversity working group. But during a recent gathering of a half-dozen Asian-American Livermore employees, five of the six said they backed the boycott as a way to put pressure on management. Says Ling-Chi Wang, the ethnic studies professor at the University of California (UC), Berkeley, who proposed the boycott: “This is a vehicle to express our collective outrage and get the message across.” Although the media spotlight has primarily been on Los Alamos, the level of distrust between employees and managers seems particularly intense at Livermore, which is located in a region with the highest proportion of Asian Americans in the country. As the Lee case snowballed last fall, nine Livermore employees submitted formal complaints charging UC—which operates both Livermore and Los Alamos—with discrimination in pay and promotion opportunities. Kalina Wong, one of the nine and a group leader in controlled materials, says management has not taken Asian-American concerns seriously enough. Adds one of the employees: “I haven't gotten a promotion in 16 years—I feel blackballed.” The complaints prompted the California Department of Fair Employment to investigate. If the department's report backs the allegations, says the group's lawyer, Jack Lee, he expects to file a class-action suit. Meanwhile, the federal EEOC is conducting its own investigation. “It's very unusual for both to be investigating the same entities,” says Lee, of the San Francisco law firm Minami, Lew & Tamaki. Livermore managers decline to discuss the investigations but dismiss the idea that there is systematic discrimination. “We've been looking at these same issues for 5 years,” says Susan Houghton, public relations chief at the lab. “And you are always going to have people who feel differently.” ## Reluctant critic George Kwei, a senior physicist who has worked at both Los Alamos and Livermore, is one of the reluctant activists. Kwei, who came from Taiwan at the age of 12, would seem to be a poster boy for Asian-American success. He arrived at Los Alamos in 1974, excelled in laser research, rose to deputy associate director at the lab, and continued vibrant research in neutron scattering. “He's done a lot of fine work in a remarkable number of fields,” says his Harvard mentor, Nobel Prize-winning chemist Dudley Herschbach. Kwei also helped Los Alamos director John Browne's office draft memos and public releases during the Lee crisis. He vociferously opposes the boycott and fears that both Los Alamos and Livermore are losing prestige. But recent events have put him in the critics' camp. He was shocked by what he felt were an intelligence official's racist comments during a lab security seminar and by the pay and promotion data passed around among Asian-American employees. So when a pet research project he proposed at Los Alamos was continuously rebuffed, and when he was passed over this summer for a senior job at Livermore for which he believes he was well qualified, Kwei says he began to wonder if his ethnicity played a role. He reached this conclusion reluctantly, he says, but last month he filed a request for an administrative review as to why he was not selected for the job. “Their response was totally unsatisfactory,” he says, adding that he has since asked for an independent review. “I could find a lawyer and sue the lab and UC,” Kwei adds. But he says the real purpose of his complaint is to underscore that management must be more aggressive in putting Asian Americans into leadership positions. Lab managers declined to discuss Kwei's case. Joseph Thompson, Kwei's former Los Alamos group leader, says he doubts Kwei's proposed project was derailed because of prejudice, and other former co-workers say that Kwei sometimes could be prickly and abrasive. But Kwei's disaffection, whatever the particular merits of his complaints, illustrate that distrust has reached the highest level. Asian Americans disagree on whether lab management and DOE are taking their concerns seriously. Kwei believes senior management at both Livermore and Los Alamos are sincerely attempting to address the problems, although he worries that that commitment drops off at lower levels. But Livermore's Dorothy Ng is skeptical that the senior management will make changes without intense pressure from DOE and employees. “If we don't hold the lab accountable, nothing will get done,” she says. DOE's Wu notes that the department is hampered by its arms-length relationship to the labs, which are run by private contractors. But he points out that Richardson last month ordered DOE's inspector general to investigate whether security clearance procedures mask racial profiling. He also recently ended a ban on foreign visitors from certain countries—including China and India—to the weapons facilities. And Wu hosted a recent conference bringing together various Asian-American researchers from around the DOE complex. DOE managers also say that they aim to give Asian-American employees a voice through a new ethnic organization. But critics say the department has made many blunders beyond the Lee case, such as last year's security video that included a woman with East Asian features in a trench coat, fedora, and carrying a spy's tiny camera. Lab managers say that they are trying to create a dialogue by promoting discussion of diversity and strengthening career-enhancement efforts. Both Browne and Livermore's Tartar have met in recent weeks with groups of Asian-American employees to discuss their concerns. With the 2001 budget out of the way, Tartar says he intends to make it a top priority. Adds Steve Younger, who leads Los Alamos's famed X division where Lee worked and which oversees the design of nuclear weapons: “It's not our intention to exclude people.” But he agrees that the lab has “its own peculiar culture—and it's a culture that needs to change.” ## Culture clash Indeed, change is coming to all the national labs, as well as to academia and industry, says Rockefeller's Ho. “How many Asian Americans do you see doing science, and how many do you see as leaders?” he asks. “There's clearly a huge gap.” Many Asian-American researchers acknowledge that smashing the glass ceiling and redressing apparent pay inequities require change within their community as well. Language difficulties can pose an obvious barrier to advancement, but many Asian-American researchers say that cultural differences discussed less openly also are holding them back. “People of Chinese, Japanese, and Korean backgrounds generally do not want to rock the boat,” says William Chu, a Korean-American biologist at Lawrence Berkeley National Laboratory in California. “It's a cultural thing.” Kwei agrees. “In general, Asian Americans have been brought up to work hard and not make waves—to let our work speak for itself.” Don Tsui, a physicist at Princeton University in New Jersey and a 1998 Nobelist born in China, says this low-key and self-effacing approach no longer is enough in the competitive world of U.S. research: “The general attitude that you just do your work is completely out of date.” U.S. researchers, he adds, must realize that “if you don't toot your horn, no one will do it for you.” Asian Americans also may have trouble adapting successfully to a system that tends to reward aggressive and outspoken individuals. “That is treasured in American culture,” says Kunxin Luo, a rising biologist with a joint appointment to Lawrence Berkeley and UC Berkeley who came from China a decade ago. “In most Asian cultures, being modest is the number-one virtue.” She recalls her difficulty in negotiating her own salary: “My American supervisor said I should be much tougher, but I just couldn't do it.” The result is a form of self-imposed discrimination in which Asian Americans avoid the managerial track and stick to the lab bench. Simon Yu, a senior high-energy physicist who has worked at Livermore and now is at Lawrence Berkeley, insists he prefers research to shuttling back and forth to Washington or chairing administrative meetings. Although he's vocal on technical issues, he acknowledges that he becomes “shy when jostling for a position.” He recalls a meeting of U.S. and European physicists where everyone literally fought for the best seat. “I told my wife that night, ‘I don't belong here.’” Americans of East Asian heritage say that they must constantly navigate the conflicting currents of their two cultures. “I've tried—consciously—to be as Americanized as I can,” says Luo, as she bustles around her office. “Until Asian-American scientists can understand the differences and purposefully try to melt into this culture a little bit better, there will be problems.” But others put an emphasis on what their native cultures can bring to the lab—such as a more careful and collaborative approach. “Since we come from a basically poor resource environment, we usually plan two or three steps ahead,” says Livermore's Joel Wong. And the East Asian tradition of collaborative efforts, as opposed to the rugged individual model of the West, is a good fit for an era of large and complex scientific endeavors, he adds. And, Wong says, “I don't want to lose my cultural traits. Each immigrant brings to this country a gift.” But the hard lesson from the Lee case, says Berkeley's Wang, is that Asian Americans must learn to play by traditional American rules when necessary: “It's fine to retain our traditional cultural values, but democracy only works for those who participate.” If you don't take part, he adds, “you'll be run over.” But there is an alternative—at least for those who have not been in the United States for generations—Wang notes. An increasing number are voting with their feet by moving to the booming universities and high-tech companies of Hong Kong, Singapore, Taiwan, and South Korea, which often offer tempting salaries, benefits, and working conditions. “The best and brightest will move on, which will hurt American science,” worries Henry Tang, chair of a New York-based group of prominent Asian Americans called the Committee of 100. Adds Wong: “So if this country wants to avoid a reverse brain drain, it will have to accommodate us.” 12. ASIAN-AMERICAN SCIENTISTS # Lee Case Births a Reluctant Activist 1. Andrew Lawler MENLO PARK, CALIFORNIA—With his black hair, lean frame, and “Far Side” T-shirt, Alex Chao looks more like a busy postdoc than a 51-year-old senior physicist at the Stanford Linear Accelerator Center (SLAC). But his 26 years at government laboratories afford him a nuanced view of the status of Asian-American researchers in the labs. Until the past year, Chao tended to keep his views to himself. “My natural inclination is to avoid this kind of thing,” he says. But the Wen Ho Lee case turned Chao into a reluctant activist who has contributed money for Lee's defense, helped organize rallies in the San Francisco Bay area, and talked to his neighbors about the injustice he believes Lee and other Asian Americans have suffered. Chao, like many Asian-American researchers, is not vocal about his own experiences as a minority scientist. The Taiwanese-born physicist says he has avoided senior managerial positions because he prefers research to bureaucracy. But when pressed, he says that wasn't always so. While serving in the 1980s on the doomed Superconducting Super Collider (SSC) project, he applied for an important management job for which he felt he was well qualified. “I cannot of course say why,” Chao says. “But I just had a feeling that I was just not being considered for the job” despite his impressive résumé. “At that time—I was young—I really cared about having a position.” But he also adds that he did not feel comfortable lobbying for the job. When the position went to a white male, he let it go and returned to SLAC, where he had worked previously. He says he is happy doing research, and he has since eschewed the management track. “I said, ‘Why should I bother?’” Chao says he's aware of a glass ceiling separating many Asian-American researchers like him from senior management. It exists even at the ethnically diverse SLAC, which solely does unclassified research and is open to scientists from around the world. “If a position comes open, or there is an important talk to give,” Chao says, managers “have a tendency to think of a person close to the person in power.” And Asian Americans “tend to be on the second list.” The discrimination is largely unconscious, he says, guided by the social net that runs through every lab. And Asian Americans themselves bear some of the responsibility, he says, because they are reluctant to voice complaints or promote their own interests. “Cultural differences make it harder to speak up,” he says, adding that this probably accounts for his own failure to pursue the SSC job more aggressively. Chao does not advocate ethnic quotas for hiring and promotion: “That sounds like strong medicine for the illness.” But in light of the Lee case, he doesn't want to let the issue of discrimination drop. He will continue his activist work—although not if it means doing less research. “My respect for our system has gone down a notch because of this,” he says. “I don't want all Chinese Americans to be seen as potential spies—I would like to have the innocence returned to this group of people.” 13. ASIAN-AMERICAN SCIENTISTS # New Breed of Protester Asks: Why Not Us? 1. Andrew Lawler BOSTON—On a rare hot night this past June in Cambridge, Massachusetts, computer science grad student Roger Hu tossed and turned in his stuffy apartment. For nearly a year he had been following with increasing anxiety the case of Wen Ho Lee, the Los Alamos National Laboratory physicist who had been arrested and jailed in New Mexico under suspicion of mishandling classified data. Unable to sleep, Hu fired off a 3:00 a.m. e-mail to a West Coast venture capitalist, an Asian American and longtime mentor to Hu. “I asked him right off—I don't know if protesting is the way to go. That seems to be something reserved for other people.” The response was immediate and unambiguous: “Let your voice be heard,” his mentor responded. “Protesting is an important aspect of the political process.” Hu took the advice, and the 22-year-old has become a key organizer among Asian-American scientists and engineers in the Boston area. Now Hu struggles to keep up with his Massachusetts Institute of Technology (MIT) classes in computer science and electrical engineering in his new life as an activist. In one 5-day period in September, he packed an MIT lecture room with students and professors for a teach-in on the Lee case, helped raise$14,000 for Lee's defense from a Boston Chinese-American group, and led a protest rally at the University of Massachusetts, Boston, the night of the first debate between presidential contenders George Bush and Al Gore. Two weeks later he was invited to a private audience with MIT President Charles Vest to discuss the Lee issue.

Such political activism, he insists, is not in his blood. With a father who is an electrical engineer, a mother who's a chemist, and two computer scientist siblings, “we sometimes call ourselves a bunch of nerds.” Nor did Hu—who was raised in Palo Alto, California, describes himself as a “diehard Bay Area kid,” and speaks in the typical lingo of California youth—learn much while he was growing up about the culture and language of his parents' native Taiwan and China. “We're entirely Westernized,” he says. And he doesn't see himself as a victim of racial bias: “I can't quite relate to discrimination, though I know it exists.”

Lee has been released from prison, but the handling of the case was an eye-opener, Hu says. During final exams last December, he was astonished to read that the federal case against the physicist was going forward. But even more disturbing, he says, was the bored reaction of his classmates when he showed them news clips. Last spring, he helped organize some small events, and “everything snowballed from there.”

Hu has energized many Asian Americans, but remains critical of the lackluster response of MIT students and faculty, who “have not really spoken out.” He did meet privately with Vest last month, at the president's request. As a result, MIT is considering hosting a forum next year on the impact of the case on Asian Americans and the scientific community. But Hu has warned: “This is a wake-up call—if you think this is over, you're wrong. We have to protest.”

14. ASIAN-AMERICAN SCIENTISTS

# Harbinger of a Litigious Future?

1. Andrew Lawler

When the chair of the pharmacology department at the University of California (UC), Davis, pledged in writing to find a permanent position for microbiologist Ronald Chuang, Chuang and his wife Linda—a researcher who works in his lab—were delighted. The position would put him on the tenure track and make him less dependent on the grants from the National Institutes of Health that powered his AIDS research.

A dozen years later, the delight has turned to anger. Ronald Chuang still has no permanent position, and he and his wife filed suit in 1997 over what they allege is a long and egregious series of discriminatory acts by the university. The university's defense team rejects the charges of discrimination, and a lower court backed the university in 1998. But 2 months ago, a federal appeals court reversed that ruling, giving a green light for the case to go to trial, perhaps in the next year.

Academics suing their institutions is hardly a new phenomenon, but Asian Americans traditionally have been far less litigious than members of many other minority groups, say university and Asian-American officials. That may be changing in the wake of the Wen Ho Lee case. “There's been a steady rise in complaints [among Asian Americans] in the past decade,” says Margaret Fung, executive director of the New York City-based Asian American Legal Defense and Education Fund. “But after Wen Ho Lee, we have heard from many more scientists and researchers who were very unhappy with their treatment.” The Lee case, she adds, “has led to a lot of mobilization” that is likely to translate into more complaints and suits. That view is seconded by other Asian Americans who work on such issues.

Originally from Taiwan, the Chuangs did their graduate work at Davis. In 1981, Ronald Chuang was made an assistant professor of pharmacology, and shortly after that, Linda Chuang became a research assistant. In 1988, the department chair wrote a memo to an assistant dean committing the school to finding a permanent position for Ronald. But that position never came through, despite five retirements in the pharmacology department after 1989. For the next decade, the Chuangs maintain that they were subjected to a pattern of racial harassment, from alleged slurs to a hallway fight—claims strongly rejected by UC Davis.

The final straw came in 1996, when the Chuangs' lab and that of another Chinese-American researcher were moved to the basement—next to the morgue—as part of a general reorganization. “No Caucasian faculty member with active research was required to relocate,” states the appeals court decision. That relocation, the court noted, “had a calamitous effect” on the Chuangs' research, as their space was reduced, the floor design complicated their work, and their offices were on the fourth floor. A technician, grad student, and undergrad quit shortly thereafter. The move also upset the Chuangs, who maintained that working so close to the morgue was particularly offensive for persons of Chinese heritage.

The Chuangs filed a complaint that year with the Equal Employment Opportunity Commission and, in 1997, they filed suit in California's eastern district U.S. court. The university argued that Ronald Chuang's position was never in jeopardy, that the dean was prepared to cover his base salary if his research grants dried up, and that the relocation was necessary to accommodate another program that was growing more quickly and was more in line with the university's long-term research plans. The district court ruled that “Ronald Chuang fails to come forward with adequate evidence” of discrimination.

But the appeals court strongly disagreed, and Peter Sandman, Chuang's attorney, says a settlement is unlikely. “The university has been utterly intransigent—it's remarkable and amazing the university does not recognize the way they've treated these people.” UC counsel Eric Behrens says “the university feels very strongly it has done nothing wrong.”

15. EVOLUTIONARY BIOLOGY

# In Search of Biological Weirdness

1. Elizabeth Pennisi

William D. Hamilton was drawn to the unusual and paradoxical. His observations led to new insights into social interactions and sex

BERKELEY, CALIFORNIA—The late William D. Hamilton (1936–2000) liked to dwell on the fringes of biology. When most of his colleagues were caught up verifying natural selection and survival of the fittest, fairly straightforward aspects of evolutionary theory, Hamilton was instead drawn to life's apparent paradoxes. Why, for instance, do individuals make sacrifices for others instead of just looking out for themselves? Or why does sex exist, given that asexual reproduction is a more efficient way to pass on all of one's genes? A dedicated student of nature—some say he was the quintessential eccentric British naturalist—Hamilton had an eye for the unusual: the fig wasp that produces mostly female progeny instead of equal numbers of both sexes, the sterile worker bee who nevertheless works hard for the good of the hive. He thought deeply about how these arrangements might have evolved.

Those thoughts and the theories that resulted have inspired a generation of evolutionary biologists, providing them “with a scientific basis for studying the weirdest possible things,” says Wayne Getz, an applied mathematician at the University of California, Berkeley. Getz, Berkeley's Phil Starks, and Robert Page of the University of California, Davis, organized a symposium here in October to honor this giant of evolutionary biology, who died of malaria in March at age 63. There, they and about 70 others discussed where Hamilton's ideas have taken them.

By studying life on biology's fringes, “you can begin to understand how the whole [of life] is constructed,” Getz explains. Just as the gaudiness of a peacock's tail helped tip off biologists that a female's choice of mate was important in evolution, extreme lifestyles and living arrangements help researchers discern other hard-to-see biological principles. A few researchers, such as Francis Ratnieks of the University of Sheffield, United Kingdom, have found exquisite support for some of Hamilton's ideas. Others, like Getz, are coming up with theories that complement those Hamilton proposed.

## All in the family

Hamilton's work on what he called inclusive fitness is seen as perhaps his most important contribution to biology. In 1963, Hamilton introduced the idea that social groups would evolve if there were enough additional benefits, in terms of passing on an individual's genes, to those participating in the group. That added benefit exists because each individual shares certain genes with relatives—the number depending on how closely related they are. So, to varying degrees, each relative's young helps perpetuate an individual's genetic legacy. Hamilton argued that participation in the group should vary according to the benefit each individual received.

He also realized that because self-interest is always partially at odds with group needs, individuals might vie to tilt the odds in favor of their own genes being passed on—even if that meant cheating on their fellow group members. As a result, conflicts could arise among group members. “The work revolutionized our understanding of reproduction, altruism, cooperation, and conflict,” says Ratnieks.

Ratnieks has been exploring the conflicts that arise in social groups of ants. “We have used inclusive fitness theory to make novel predictions about areas of social life that were not [explicitly] covered by the theory before,” he explains. In particular, he and Sheffield's Thibaud Monnin have been looking at how hierarchies develop and persist within ant colonies and how worker ants make sure that as many of their genes as possible are passed on even though they themselves are not laying any eggs.

In preliminary research with several large ant species belonging to the genus Dinoponera, Ratnieks has found how members of the colony keep other members from gaining a reproductive edge over their nest mates and, in the process, make it less attractive for other ants to even try to gain that edge. In this way, workers maximize the size of their genetic bequest in each egg laid. “[Hamilton's] theory [is] remarkably close to what is observed,” says Ratnieks.

In these colonies, all ants look alike and can reproduce; there is no queen, as there is in a honeybee hive. But the ants nevertheless have adopted a hierarchical structure in which one alpha ant, or “top dog,” does almost all the reproducing. After she mates with a male at the start of her reproductive life—which she does just once—she does little else besides lay eggs. The majority of other ants are workers who forage for food, tend the eggs, and maintain the nest. They are at the low end of the pecking order. In between are several high-ranking ants called “hopeful nonworkers”: They don't work and try to become egg-layers instead.

Given the appeal of that easy life, Hamilton's theory would predict that lots of workers would opt to be hopeful nonworkers, taking the chance that they would eventually become the egg-layer—the one who gets to pass on her genes all the time. But only a few do, so Ratnieks and his colleagues decided to figure out why.

One reason, Ratnieks and his colleagues found, is that the life of a hopeful nonworker is a rough one—and that provides one clear disincentive to many ants that would otherwise strive to move up in the hierarchy. Both the alpha ant and many workers try to prevent any upwardly mobile ants from laying eggs. The alpha female often grabs the antenna of her rival, preventing it from bullying lower ranking individuals. Sometimes, she bites a rival's antenna and rubs it against her belly, as if to make clear who is boss. Combining forces, a number of workers will each grab the leg or antenna of an uppity individual, particularly the number-two ant, holding her spread-eagle “sometimes for days,” says Ratnieks. By that time, she is sufficiently intimidated and likely will be unable to lay eggs. The worker ants' reaction to hopeful nonworkers fits well with Hamilton's view, as individuals are working to maintain their own self-interest even as they are contributing to group living.

In terms of self-interest, this policing behavior makes sense because most of the workers—including the upstart rivals—are daughters of the egg-laying alpha ant. Hamilton would have predicted that because more of the workers' genes are passed on when their mom reproduces than when their sister does, the workers would prefer to have their mom do all the egg-laying. That's second only to being able to lay the eggs themselves. “It's not in their interest” for workers to allow the alpha female to be replaced, explains Ratnieks. Moreover, each ant that becomes a hopeful nonworker diminishes the colony's productivity; if too many ants make that choice, the colony as a whole suffers. Although these results are preliminary, they are “an extremely clear and elegant application of Hamilton's inclusive fitness theory to explain social interactions and conflicts,” comments Stuart West, an evolutionary biologist at the University of Edinburgh, United Kingdom.

## The when and why of sex

Sex—specifically, why it is necessary—was another of Hamilton's pet problems. Asexual reproduction seems the most efficient way to pass one's genes to the next generation, as each offspring is essentially a clone carrying 100% of the parent's DNA; in sexual reproduction, by contrast, each parent contributes only half. But sex persists—indeed, it is the dominant form of reproduction among vertebrates and exists in many other kinds of organisms. Geneticists have come up with one explanation for the persistence of sex. In asexual reproduction, they suggest, the clones would accumulate genetic mutations through successive generations that would eventually render the organism dysfunctional. Sexual reproduction could help remove these mutations, as parents with one bad and one good copy of a gene can each pass that good copy on to the offspring, removing the bad copies from the genome.

But Hamilton had a different idea: Only through genetic variety, which sexual reproduction brings, could organisms have any hope of outwitting parasites. In the evolutionary arms race, microbes reproduce and change so quickly that they can rapidly evolve ways to avoid the host's defenses. The new combinations of genes that sex provides give the host a much-needed edge—an advantage that outweighs that of passing on a full set of genes, Hamilton suggested.

Neither of these theories has thoroughly convinced researchers. For one, they don't explain why some organisms have switched back and forth between the two forms of reproduction over evolutionary time, sometimes practicing both. Nor do they explain why others, such as the much-studied group of single-celled aquatic organisms called bdelloid rotifers, don't bother with sex at all.

Now Getz thinks he has an answer to why organisms might be sexual, asexual, or both. He has developed a mathematical model that enables him to predict which type of reproduction will exist within a community. The model assumes that each clone produced by asexual individuals will use the local resources in the same way; sexual reproduction, on the other hand, will provide different gene combinations that enable offspring to exploit the environment in multiple ways.

If the environment never changes, clones could win out, simply because their genes would come to dominate the population. But the model shows that the more the environment fluctuates, the more likely it is that only sexual organisms will succeed. Under conditions of modest change, though, the two modes of reproduction can coexist, with the reproductive capacity of clones balancing out the survival capacity of the sexuals. Getz thinks this hypothesis might explain the coexistence of asexual and sexual species within particular genera of soil mites. As for asexual rotifers, Getz proposes that they have a different way of avoiding extinction when their environment changes. Rotifers can survive droughts, because their eggs desiccate and persist in the soil until rehydrated when the right environment “returns.”

“[Getz] provides an interesting new perspective,” says Lotta Sundström, an evolutionary biologist at the University of Helsinki, Finland. However, she and West both caution that Getz has not captured the full picture. West in particular thinks the best model will be more inclusive and will factor in the value of sexual reproduction in ridding the genome of mutations and also in enabling organisms to deal with parasites.

Getz takes their criticism in stride. Like Hamilton, he's open to considering a wide range of possibilities about how life works and gives serious thought even to farfetched ideas. Hamilton's career, he notes, demonstrated how such open-mindedness can have great rewards. “When we begin to think with a Hamiltonian frame of mind,” Getz explains, “it allows us to consider astonishing kinds of phenomena”—and sometimes even figure them out.

16. EVOLUTIONARY GENETICS

# Europeans Trace Ancestry to Paleolithic People

1. Ann Gibbons

Y chromosome data show that living Europeans have deep roots in the region—and researchers say genetic markers may be linked to archaeological cultures known from archaeology

About 8000 years ago, the people living in Franchthi Cave in southern Greece experienced a dramatic change of lifestyle. On the floor of the cave where hunter-gatherers had been dropping stone tools and fishbones for thousands of years, the remains of a new kind of feast appear: traces of wheat, barley, sheep, and goat, which can only be the result of farming and herding animals. Within the next 3000 years, the same abrupt transition ripples through archaeological sites along the shoreline of the Mediterranean, eventually reaching Europe, where settled villages of mud-brick houses appear. “The consequences of the transition were fundamental—village settlement, new beliefs, different social structure,” says archaeologist Colin Renfrew of the University of Cambridge in England. “A behavioral revolution took place.”

But which people made that revolutionary European transition? Did farmers move into Europe from the Fertile Crescent in the Middle East, or did local hunter-gatherers learn to trade and farm themselves? And if Neolithic newcomers brought farming technology, did they replace most of the locals, or did those Paleolithic locals survive and become the primary ancestors of modern Europeans?

Now, after years of debate, these questions are being answered not only by ancient remains but also by the genes of living Europeans. In a report on page 1155, an international team reports that a wealth of data from the Y chromosome show that it was the local hunter-gatherers who passed on more of their genes. More than 80% of European men have inherited their Y chromosomes—which are transmitted only from father to son—from Paleolithic ancestors who lived 25,000 to 40,000 years ago. Only 20% of Europeans trace their Y chromosome ancestry to Neolithic farmers. Thus, the genetic template for European men was set as early as 40,000 years ago, then modified—but not recast—by the Neolithic farmers about 10,000 years ago.

These Y chromosome data are “strikingly similar” to new findings on mitochondrial DNA (mtDNA), which is inherited maternally, notes evolutionary geneticist Martin Richards of the University of Huddersfield in England, who led a mtDNA study published in the November issue of the American Journal of Human Genetics. “A consensus is emerging on what the genetic data are telling us,” says Richards. “After all the debate, this is very exciting and encouraging.”

The data from both genetic lineages not only enable researchers to trace the movements of the first farmers, they also paint a remarkably detailed picture of the identity and movements of ancient Europeans. The Y chromosome team, led by geneticists Ornella Semino of the University of Pavia in Italy and Giuseppe Passarino of Stanford University, also took the bold step of explicitly connecting genetic and archaeological data—a move that is already drawing some fire. The researchers link two early migrations recorded by the Y chromosome to two Paleolithic cultures, the Aurignacian and Gravettian, each famous for their spectacular art and artifacts (see map). “This paper shows us that molecular genetics is beginning to show us which genetic markers are coordinated with climatic events and population dispersals,” says Renfrew.

The earliest glimpse of European genetic origins came from protein markers; more recently, researchers studied the mtDNA of European women. But the results were divided: One group of researchers that included Stanford geneticist L. Luca Cavalli-Sforza, a co-author of the new Y chromosome study, found similar markers in Europeans and Middle Easterners, which declined from east to west and looked like the signature of the Neolithic expansion. But other researchers proposed that several European genetic markers were too old to have been introduced with the Neolithic newcomers.

The obvious way to reconcile the sometimes heated debate was to look at men's genetic history as recorded on the Y chromosome. By comparing the variations, called polymorphisms or markers, at one site on the chromosome, and the frequency at which those variations occur in different populations, geneticists can sort out which populations are most closely related. They can then build a phylogenetic tree that traces the inheritance of the Y chromosome markers in different populations. And by using average mutation rates, researchers can estimate how long ago particular mutations appeared, thus dating various population splits and movements.

Using samples from 1007 European men, the Y chromosome team got clear results: Most of the men could be sorted into 10 different Y chromosome variants or haplotypes. The researchers sorted those haplotypes on a phylogenetic tree and used the geographic distributions of modern markers to trace the evolution and spread of the ancient markers. For example, they found that four modern haplotypes, which account for 80% of European men's Y chromosomes, were descended from two now-vanished haplotypes. One, M173, arose more than 40,000 years ago from an even older marker called M45. Apparently M45 was present in men living in Asia, for other descendants of this haplotype are now seen in Siberians and Native Americans. Meanwhile, the descendants of the M173 marker are found at the highest frequency today in Europe. So the researchers conclude that M173 is an ancient Eurasiatic marker that moved into Europe about 35,000 to 40,000 years ago.

The authors note that this is just the time of the advent of the Aurignacian, an advanced culture that reached its height in Western Europe about 35,000 years ago and is well-known for its sophisticated rock-art paintings and finely crafted tools of antler, bone, and ivory. Archaeologists have hotly debated whether these people originally came from Europe, Asia, or the Middle East. Now the authors propose that haplotype M173 is the “signature of the Aurignacian,” and that these people came from central Asia. If the team is right, then half of modern European men still carry the genetic signature of these ancient artists.

Using similar reasoning, the researchers report that the next wave of migration into Europe, marked by a mutation known as M170, occurred about 22,000 years ago from the Middle East. The authors link this wave to the so-called Gravettian culture, known for its Venus figurines and small, delicate blades, which first appeared in the area that is now Austria, the Czech Republic, and the northern Balkans. But archaeologist Alison Brooks of George Washington University in Washington, D.C., warns that there were many cultures in Europe at these times, such as the Solutrean from Iberia, and that it's risky to link genes to a particular culture.

Once in Europe, the timing and geographical distribution of markers suggests that Aurignacian people dominated Western and southern Europe, while the Gravettian people thrived in Eastern and Central Europe. But when the climate worsened during the Last Glacial Maximum 24,000 to 16,000 years ago, people carrying the “Aurignacian” marker apparently concentrated in refuges in the Iberian peninsula and the Ukraine. Meanwhile, the Gravettian people apparently moved to the Balkans. After the glaciers retreated, the geneticists say that these people moved out of the refuges and their populations expanded rapidly. That fast expansion is why these markers now account for such a large proportion—80%—of modern Europeans' Y chromosomes.

Finally, another migration occurred, marked by four new mutations about 9000 years ago, apparently in men coming from the Middle East. But only about 20% of Europeans have these Neolithic markers. The authors tie this migration to the spread of farming out of the Fertile Crescent, as seen in the archaeological record. The distribution of markers even suggests something about the route the ancient farmers took: “There's more Paleolithic [markers] in the north of Europe than the south and more Neolithic in the south,” says Cavalli-Sforza. “I believe at least part of the Neolithic people went by boat along the coast.”

The new mtDNA data tell much the same tale, says Richards, with 80% of European women having the older Paleolithic markers and 20% having Neolithic markers—although in women, the Neolithic haplotypes are not concentrated along the Mediterranean coastline, a finding that could reflect the different movements of the sexes. But the mtDNA data also suggest the presence of ice age refuges in Iberia and, to a lesser extent, southern Europe. “This fits completely with the mitochondrial data that show an expansion out of Iberia,” says Antonio Torroni, a geneticist at the University of Urbino in Italy who proposed the idea of an Iberian refuge in 1998.

The new Y chromosome data enhance the existing picture, says Renfrew. “The mitochondrial work showed us the way, but the Y is making it even more clear,” as the Y chromosome data reveal geographical sources of origin more clearly. This is probably because in many societies women move to join their husband's families, while related men cluster more closely geographically. And because some men have many, many children, they leave more offspring with identical Y chromosomes—and a sharp geographical signal.

But those features also mean that there is less diversity in Y chromosome lineages around the world than in mtDNA, notes Cavalli-Sforza. That lack of diversity makes dating the Y chromosome mutations more difficult: In their calculations, researchers assume that low genetic diversity means that less time has passed—but instead, men's mating habits might be creating a pool of very similar DNA and swamping the data. That would cause researchers to underestimate the age of genetic and population events.

Some researchers are particularly wary of connecting these roughly dated markers to cultures known from the archaeological record. Although he praises the basic Y chromosome results, “I don't like attaching genetics to archaeological evidence,” says Mark Jobling, a geneticist at the University of Leicester in England who also studies the Y chromosome in Europeans. “It appeals to the imagination, but the mutation rates on the Y [and therefore the dating of genetic events] have wide confidence margins.”

Cavalli-Sforza agrees that genetic dates have large margins of error. But because even these preliminary dates from different genetic lineages correspond well with each other and with major migrations suggested by the archaeological record, it is hard to resist making the connections. “Genetic dating is in its infancy,” says Cavalli-Sforza. “We have to start somewhere. The future will bring new evidence.”