Twelve years ago scientists at the University of California, Berkeley, concluded from DNA studies that “Eve” an ancestor common to all modern humans, was an African. Now scientists in South Africa have tracked “Eve” to the Khoisan peoples, who are the oldest indigenous group in southern Africa
To pinpoint Eve's origins, geneticists Himla Soodyall and Trefor Jenkins of the South African Institute for Medical Research and the University of the Witwatersrand in Johannesburg analyzed mitochondrial DNA (mtDNA), genetic material from the energy-producing organelles in all cells. Because after conception only the egg's mitochondria survive, mtDNA forms a continuous thread running back in time through the maternal lineage. Knowing mtDNA mutation rates, scientists can infer, by comparing DNA segments from different populations, which are the most ancient patterns.
The researchers drew blood from 100 people from two Khoisan groups and compared the mtDNA sequences with those from 50 other sub-Saharan Africans. Soodyall says the study found that some 84% of the mtDNA types they looked at were “unique” to the Khoisan and could be dated back to 120,000 years ago. This demonstrates that “some of the most ancestral signatures in mtDNA are still found in living Khoisan people,” she says. The same sequences have been lost due to random mutations in other, later populations.
The findings, presented at a recent human evolution meeting at Cold Spring Harbor Laboratory in New York, complement data from the male side: Y chromosome studies had previously pegged the Khoisan among a handful of groups with Y chromosomes most closely resembling those of a common ancestor who lived in Africa 145,000 years ago (Science, 31 October 1997, p. 804). Mike Hammer of the University of Arizona, Tucson, who took part in the Y chromosome study, says the latest mtDNA work provides “important confirmation” of the team's work.
A Penny for Your Stocks
U.S. stock exchanges are about to take a giant step out of the 18th century. The Securities Industry Association, an organization of more than 740 banks and brokerage firms, last week unveiled a plan to convert stock prices from fractions of a dollar to decimals. Instead of buying stocks at tongue-twisting prices like 7 11/16, investors will be able to buy them at $7.70
The old system was a holdover from the late 1700s, when the unit of currency for trading was the Spanish gold dollar, and it was easier to break a coin into halves or quarters than it was to split it into tenths. The conversion to decimal units—which are already used in most foreign markets—will take place from July to October 2000. Initially, prices will move in 5-cent increments, but after October the market will determine the increments.
If markets move to 1-cent increments, message traffic on exchange computers will more than double by 2001 as prices are able to respond to tiny oscillations in demand, according to a study by SRI Consulting in Menlo Park, California. Although the number of trades would increase by 80%—a not unhappy prospect for traders working on commission—the volume, or money value of what's traded, would only increase marginally, by perhaps 9%, says SRI.
Boston Tea Party
How do you get a gaggle of Nobel laureates, including Harvard chemist Dudley Herschbach and physicist Sheldon Glashow, to dress up as sheep? Have them star in an opera celebrating human-cloning pioneer-wannabe Richard Seed, of course. Alas, this far-off Broadway production won't be coming to a theater near you: It was just a teaser for this year's winners of the 1999 Ig Nobel Prizes.
The awards, a spoof on the real McCoy, were handed out at Harvard University last week to 10 scientists or teams whose achievements “cannot or should not be reproduced,” at least in the sober judgment of the Annals of Improbable Research, a humor journal. The physics prize was shared by Len Fisher of the University of Bristol, U.K., for his insights into the optimal technique for dunking biscuits in tea, and Jean-Marc Vanden-Brock of the University of East Anglia, U.K., for showing how to make a drip-proof teapot. And—a sign of a field steeped in tradition but still hot—the British Standards Institution received the literature prize for its six-page treatise on how to make a proper spot of tea.
Finally, the Ig Nobel Peace Prize, like the Nobel itself, has found a worthy recipient in South Africa: Charl Fourie and Michelle Wong of Johannesburg were honored for a car alarm that prevents theft by employing a flame-thrower. For more on the prizes, see http://www.improbable.com./
Glacier Man a Spring Chicken
The results of radiocarbon dating are in: The corpse found in a British Columbia glacier last summer is only about 550 years old—and not, as some fancied, up to 10,000 (Science, 3 September, p. 1485). Stumbled upon by two sheep hunters in August, the man was accompanied by various tools, but nothing about the find was an obvious giveaway to his age. The Champagne and Aishihik First Nations, on whose land the body was found, say they are pleased with the results. Accompanied by a finely woven hat, leather pouch, fur cloak, and various tools, the glacier man offers valuable information on “pre-[European] contact clothing, tools, and land-use patterns,” says Champagne and Aishihik chief Bob Charlie. Scientists looking for insights into the peopling of the Americas, however, will have to hope for a more ancient vintage the next time around.