Research on lifespan and DNA - new discovery

Very interesting, especially the finding that rate of mutations varies greatly between species. This is relevant to theories of human origins, because the "Out of Africa" theory is based on the finding that there's more genetic variation within Sub-Saharan Africa than in rest of world put together, which is assumed to mean that Sub-Saharan Africans have been here longest, and are therefore the original humans from whom all others descended. But if rate of mutation varies between species maybe it also varies between races or simply between environments?