For GSS Losing Biodiversity chapter 4. Excerpt: ...In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years. The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found. ...“The more we learn from the DNA extracted from these fossils, the more complicated the story becomes,” Dr. Shapiro said. This complicated story has come to light only because of advances over the past 20 years in retrieving ancient DNA. When an organism dies, its DNA breaks down into smaller and smaller fragments, while also becoming contaminated with the DNA of other species like soil bacteria. So piecing the fossil DNA together is a bit like putting together a jigsaw puzzle created by a sadist.... http://www.nytimes.com/2013/12/05/science/at-400000-years-oldest-human-dna-yet-found-raises-new-mysteries.html, Carl Simmer, The New York Times.
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