Word: dna
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Dates: during 2000-2009
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...researchers, including lead author Kay Wilhelm, soon realized they were sitting on a goldmine: hundreds of detailed personal histories covering 25 years that were perfectly suited to the testing of a brand new discovery. Some 127 of the original group - now mostly in their early 50s - agreed to give dna samples, which were crosschecked with their life stories. The result is a guide for working out depression risk: for example, a person with the high-risk genotype who experiences three or more adverse life events in a year has an 80% risk of becoming depressed, compared with a 30% risk...
...skeptics, who would question whether it's feasible to target something as vague as pre-onset depression. That goal would become especially problematic should the research lead to wider use of antidepressants, shown to cause moderate to profound agitation in 7% of users. And will people need a dna test to find out their genetic vulnerability to depression? There is probably some personality marker for the high-risk genotype, says Parker. Despite a trawl of the data, however, "we haven't found it yet. We've looked at all varieties of anxiety and numerous personality styles," but at this stage...
...performed, should reveal plenty about Kennewick Man's diet. Says Stafford: "We can tell if he ate nothing but plants, predominantly meat or a mixture of the two." The researchers may be able to determine whether he preferred meat or fish. It's even possible that DNA could be extracted and analyzed someday...
...well. Could there have been multiple waves of migration along a variety of different routes? One way scientists have tried to get a handle on that question is through genetics. Their studies have focused on two different types of evidence extracted from the cells of modern Native Americans: mitochondrial DNA, which resides outside the nuclei of cells and is passed down only through the mother; and the Y chromosome, which is passed down only from father to son. Since DNA changes subtly over the generations, it serves as a sort of molecular clock, and by measuring differences between populations...
...least you can try. Those molecular clocks are still rather crude. "The mitochondrial DNA signals a migration up to 30,000 years ago," says research geneticist Michael Hammer of the University of Arizona. "But the Y suggests that it occurred within the last 20,000 years." That's quite a discrepancy. Nevertheless, Hammer believes that the evidence is consistent with a single pulse of migration...