The exclusively female origin of all the mitochondria in an embryo has an important consequence. All humans—male or female—must have inherited their mitochondria from their mothers, who inherited their mitochondria from their mothers, and so forth, in an unbroken line of female ancestry stretching indefinitely into the past. (A woman also carries the mitochondrial genomes of all her future descendants in her cells; ironically, if there is such a thing as a “homunculus,” then it is exclusively female in origin—technically, a “femunculus”?)
