Posted on Friday 10 December 2004

After the dinosaurs were wiped out 65 million years ago by, um, well... whatever wiped them out, mammals (originally tiny mouse-like creatures) suddenly went through a dramatic explosion of speciation, rapidly diversifying in shape and size to fill the vast number of ecological niches that had been suddenly vacated.
Evidence of this explosion is written on the genes of every mammal alive today, all of whom share a surprisingly high amount of DNA from this extinct species and some remarkable recent research using a segment of DNA from 19 different mammalian species has been able to reconstruct what the equivalent sequence of the ancestor species' DNA would have looked like. The reconstruction is claimed to be more than 98% accurate.
While generating a sequence of a million base-pairs is still a far cry from reconstructing the DNA of an entire creature, the implications of this research are quite exciting because it has the potential of enabling us to work out the most likely trajectory of mutations our genome took as it rolled through mammalian history. This offers us opportunities to test the genetic capabilities of our ancestors, their metabolisms, their ability to see colour and so on which is something never thought possible before because fossilized DNA cannot be extracted from bones more than 50,000 years old. This new technique allows us to go back 80 million!
The New York Times has a good rundown on this research (free_-kin' registration required).