The holder of this title is believed by some to have lived about 140,000 years ago in what is now Ethiopia, Kenya or Tanzania. The time she lived is calculated based on the molecular clock technique of correlating elapsed time with observed genetic drift.
Mitochondrial Eve is the most recent common ancestor of all human via the mitochondrial DNA pathway, not the unqualified MRCA of all humanity. All living humans can trace their ancestry back to the MRCA via at least one of their parents, but Mitochondrial Eve can only be reached via the maternal line. Therefore, she necessarily lived much longer ago than the MRCA of all humanity.
If she is everyone's great great Grandmother, many centuries removed, then we're all cousins and AFRICAN-Whatevers!!!
"If she is everyone's great great Grandmother, many centuries removed, then we're all cousins and AFRICAN-Whatevers!!!"
But where does the infusion of alien DNA fit in? I mean, perhaps we are all Vulcan-whatevers.