domingo, 25 de diciembre de 2016

Why we're closer than ever to a timeline for human evolution


An artist’s rendering of Sima de los Huesos hominins, estimated to have lived approximately 400,000 years ago. Photograph: Kennis & Kennis/AP

Dating when our ancestors split from Neanderthals and other relatives has long been a puzzle, but DNA advances are making our evolutionary journey clearer

Anthropologists and geneticists had a problem. And the farther back in time they looked, the bigger the problem became.

For the past several years, there have been two main genetic methods to date evolutionary divergences - when our ancestors split from Neanderthals, chimpanzees, and other relatives. The problem was, the results of these methods differed by nearly two-fold.

By one estimate, modern humans split from Neanderthals roughly 300,000 years ago. By the other, the split was closer to 600,000 years ago. Likewise, modern humans and chimps may have diverged around 6.5 or 13 million years ago.

Puzzled by this wild disagreement, researchers with diverse expertise have been studying it from different angles. Their combined discoveries, recently reviewed here and here, have shed light on how genetic differences accumulate over time and have advanced methods of genetic dating. [...] The Guardian