RFLP map of human
mtDNA variation: "The
Mitochondrial Eve"
Becky
Cann, Mark Stoneking, and Allan Wilson obtained mitochondrial
DNA (mtDNA) from the placentas of 113 women of
various continental origins. Comparative analysis of 398
variable restriction sites in their RFLP maps showed
that seven women of African descent (lower right corner)
formed a related
clade that diverged early in the evolution of Anatomically
Modern Humans (AMHs) from all other women (including
others of African origin). This finding was consistent with
an African origin of all modern humans,
(the "Out of Africa" hypothesis). The
calculated divergence divergence time of the most recent
common ancestor (the so-called "Mitochondrial
Eve") placed her far more recently that
previously supposed, less than 200,000 years ago.
It must be emphasized that the occurence of an "Eve" for mtDNA is a consequence of a population genetic phenomenon coalescence, where any gene traces backwards in time to a single common ancestor, and does not mean that she was the only woman alive at that time.
It must be emphasized that the occurence of an "Eve" for mtDNA is a consequence of a population genetic phenomenon coalescence, where any gene traces backwards in time to a single common ancestor, and does not mean that she was the only woman alive at that time.
Figure from Cann, Stoneking, & Wilson (1987) "Nature," 325:31; additional text © 2012 by Steven M. Carr