From Brian Switek at Nature:
A study1 published 2 March in PLOS Genetics gives a rare insight into how genomes change as a species dies out. Towards the end of the last Ice Age, around 11,700 years ago, woolly mammoths ranged through Siberia and into the colder stretches of North America. But by about 4,000 years ago, mainland mammoths had died out and only 300 remained on Wrangel Island off the Siberian coast.
In order to examine this disappearance at the genetic level, biologists Rebekah Rogers and Montgomery Slatkin at the University of California, Berkeley, compared the complete genome of a mainland mammoth (Mammuthus primigenius) that lived about 45,000 years ago with that of a Wrangel Island mammoth from about 4,300 years ago. The sequences were made available by Love Dalén at the Swedish Museum of Natural History in Stockholm.
“As I looked at the sequence data,” says Rogers, “it became very clear that the Wrangel mammoth had an excess of what looked like bad mutations.” More.
That’s a useful insight for conservation, as the authors point out: One wants genomes from the middle of the stream, not the swampy shallows.
It also raises the question whether mass extinctions, say, of the trilobites or the dinosaurs (when examples of many other classifications of life form survived) had a genetic component.
See also: Extinction: Can New Zealand extirpate invasive species?
Researchers: The dinosaurs died of darkness and cold
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