Wednesday, November 19, 2008

Cutting Edge techniques to do Ancient Science

Now they've sequenced the woolly mammoth! How awesome is that?! Not only have they sequenced about 80% of its genome, but they've discerned that they're very closely related to modern elephants (already suspected, of course), and they may have an idea as to why they went extinct!

Just amazing stuff you can tell from a DNA sequence. They were able to get a sample of mammoth DNA from hair of the mammoth. There are some amazingly preserved specimens of the mammoth discovered over the years. Some specimens were so well preserved in ice that the meat is still edible (no word on if it tastes like chicken).

But an analysis of the DNA sequence led by Stephan Schuster lab at Penn State University with Webb Miller as primary author and published in Nature showed that elephants and mammoths are very closely related at a genetic level with a difference of 0.6%, half that of humans and chimpanzees. Furthermore, at an estimated 4.7 billion base pairs, it's 1.4 times the size of the human genome.

They sequenced genomes from several specimens of woolly mammoth and discovered that there was indication of inbreeding among mammoth populations, and not a great deal of genetic diversity. For a species, this is bad news. It means that the entire population is susceptible to being wiped out by disease or climate changes. It could indicate why the mammoth went extinct--simply because there wasn't enough to choose from in the pool of genes within the mammoth population to create individuals who could combat environmental or health stresses.

Nature will charge for access to the article, but you can read a description about it here

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