Adam and Eve

Mme Degioanni made a good point today. She asked us if there was an incompatibility with the fact that the mitochondrial ‘Eve’ is dated at around 200ky and that a similar study based on the Y-chromosome study (‘Adam’) cites a last common ancestor at around 90ky. Eve never met Adam! Nobody in the class could give an answer, but when she explained the reason it seemed so obvious.

These studies are based on today's modern populations, so any haplotypes that went extinct are not represented.  Had they used a sample from say 100 or 1000 years ago, the picture could be quite different, potentially pushing the LCA estimate back. 

That's the nature of the beast with classic mtDNA analyses. This is why recent breakthroughs in using fossil DNA is so exciting. Seeing snapshots in the past will help correct the bias inherent in using a sample from today's existing haplotypes.