Mitochondrial Eve

In the field of human genetics, Mitochondrial Eve refers to the matrilineal most recent common ancestor (MRCA) of modern humans. In other words, she was the most recent woman from whom all living humans today descend, on their mother's side, and through the mothers of those mothers and so on, back until all lines converge on one person. Because all mitochondrial DNA (mtDNA) is generally passed from mother to offspring without recombination, all mtDNA in every living person is directly descended from hers by definition. Mitochondrial Eve is the female counterpart of Y-chromosomal Adam, the patrilineal most recent common ancestor, although they lived thousands of years apart.

Each ancestor (of people now living) in the line back to the matrilineal MRCA had female contemporaries such as sisters, female cousins, etc. and some of these female contemporaries may have descendants living now (with one or more males in their descendancy line). But none of the female contemporaries of the "Mitochondrial Eve" has descendants living now in an unbroken female line.

Mutation and isolation over time has changed the way people look. If it was not this way we would all look alike according to Mitochondrial Eve.