Interviewee: Mark Stoneking.
Geneticist Mark Stoneking speaks about the findings of early mitochondrial DNA studies.
(DNAi Location: Applications > Human origins > Gene genealogy > Tracing ancestries > Constructing our family tree)
Transcript:
What we could do was to construct a genealogy, a phylogenic tree, relating mitochondrial DNA types based on the idea that the fewer the number of differences, the fewer the number of mutations we see, the more closely related they are. And the greater number of mutations the more distantly related they are. So we could use this idea to link everything up into one phylogeny, one tree, which is really then a maternal genealogy of the human species. And what we found was that the deepest branches in this genealogy, the first split in this genealogy, separated a group of African mitochondrial DNAs from everyone else in the world, including many African mitochondrial DNA types. And so that pattern strongly suggests that the common ancestor then lived in Africa because that's the only place where you have individuals falling on both sides of this deep split.
This illustration shows the two major mitochondrial DNA lineages. The lower branch includes only African populations. The upper branch has both African and non-African members.