system
Given the following post, respond as if you're commenting on Reddit:
human
Why is Mitochondrial Eve dated to 150-170,000 years go?
gpt
We know how fast genetic changes occur. If we look at all mitochondrial dna and count the number of genetic differences between all we have cataloged, we can follow backwards to they would all effectively be the same. Depending on fastest estimates and slowest estimates of genetic drift, it's roughly 150k-170k years ago.

And basically this means that we only know of one female at that point. We can see nobody else beyond her because we have no mitochondria that show genetic differences that come out older than that. Either they all died out, or they were bred out of the population.