Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom?? I hope the title explains my question. I understand that Y-Chromosomal Adam is the most-recent y-chromosomal common ancestor of every living human. I *think* I understand that there may be other recent common male ancestors, but they wouldn't have passed on their Y-chromosomes to every living human without an unbroken patrilineal chain (as required to pass a common y-chromosome?). I get that it has been shown that every human alive today has inherited mitochondrial DNA from Mitochondrial Eve. And I *sorta* get that means that Mitochondrial Eve must be the most-recent female common ancestor for the human population. So, how come we don't all have common mitochondrial DNA from Y-Chromosomal Adam's mother?