Million-year-old DNA sheds light on the genomic history of mammoths

[T_aquaticus]

Million year old DNA sequenced. Impressive.

Temporal genomic data hold great potential for studying evolutionary processes such as speciation. However, sampling across speciation events would, in many cases, require genomic time series that stretch well back into the Early Pleistocene subepoch. Although theoretical models suggest that DNA should survive on this timescale1, the oldest genomic data recovered so far are from a horse specimen dated to 780–560 thousand years ago2. Here we report the recovery of genome-wide data from three mammoth specimens dating to the Early and Middle Pleistocene subepochs, two of which are more than one million years old. We find that two distinct mammoth lineages were present in eastern Siberia during the Early Pleistocene. One of these lineages gave rise to the woolly mammoth and the other represents a previously unrecognized lineage that was ancestral to the first mammoths to colonize North America. Our analyses reveal that the Columbian mammoth of North America traces its ancestry to a Middle Pleistocene hybridization between these two lineages, with roughly equal admixture proportions. Finally, we show that the majority of protein-coding changes associated with cold adaptation in woolly mammoths were already present one million years ago. These findings highlight the potential of deep-time palaeogenomics to expand our understanding of speciation and long-term adaptive evolution.
Million-year-old DNA sheds light on the genomic history of mammoths | Nature

[Dan_Eastwood]

I’m really impressed the the computational methods have come so far to be able to do this sort of reconstruction.

[Rumraket (Mikkel R.)]

Yep, same. And the million year preservation of DNA too.

[Rumraket (Mikkel R.)]

It might not remain the record for long though. It seems Mary Schweitzer and colleagues have found evidence for DNA fragments in dinosaur bones.

Evidence of proteins, chromosomes and chemical markers of DNA in...

[swamidass (S. Joshua Swamidass)]

I thought that was just protein?

[Rumraket (Mikkel R.)]

So did I until I read that paper. Short of sequencing the evidence they present seems pretty solid to me. Question is how intact it is, if it really is DNA.