miércoles, 26 de marzo de 2014

Human evolution: The Neanderthal in the family

Thirty years after the study of ancient DNA began, it promises to upend our view of the past.

Photo Adapted from: Tetra Images/Alamy
  Before ancient DNA exposed the sexual proclivities of Neanderthals or the ancestry of the first Americans, there was the quagga.

An equine oddity with the head of a zebra and the rump of a donkey, the last quagga (Equus quagga quagga) died in 1883. A century later, researchers published1 around 200 nucleotides sequenced from a 140-year-old piece of quagga muscle. Those scraps of DNA — the first genetic secrets pulled from a long-dead organism — revealed that the quagga was distinct from the mountain zebra (Equus zebra).

More significantly, the research showed that from then on, examining fossils would no longer be the only way to probe extinct life. “If the long-term survival of DNA proves to be a general phenomenon,” geneticists Russell Higuchi and Allan Wilson of the University of California, Berkeley, and their colleagues noted in their quagga paper1, “several fields including palaeontology, evolutionary biology, archaeology and forensic science may benefit.”

At first, progress was fitful. Concerns over the authenticity of ancient-DNA research fuelled schisms in the field and deep scepticism outside it. But this has faded, thanks to laboratory rigour that borders on paranoia and sequencing techniques that help researchers to identify and exclude contaminating modern DNA. [...] nature.com/