African Populations and the Evolution of Human Mitochondrial DNA

Abstract

The proposal that all mitochondrial DNA (mtDNA) types in contemporary humans stem from a common ancestor present in an African population some 200,000 years ago has attracted much attention. To study this proposal further, two hypervariable segments of mtDNA were sequenced from 189 people of diverse geographic origin, including 121 native Africans. Geographic specificity was observed in that identical mtDNA types are shared within but not between populations. A tree relating these mtDNA sequences to one another and to a chimpanzee sequence has many deep branches leading exclusively to African mtDNAs. An African origin for human mtDNA is supported by two statistical tests. With the use of the chimpanzee and human sequences to calibrate the rate of mtDNA evolution, the age of the common human mtDNA ancestor is placed between 166,000 and 249,000 years. These results thus support and extend the African origin hypothesis of human mtDNA evolution.

Mitochondrial DNA polymorphisms in Yunnan nationalities in China

“…Although restriction enzyme analyses represent polymorphism over the whole mitochondrial genome, some ambiguities remain with respect to the actual number of nucleotide differences and with respect to the estimation of genetic distances Horai and Hayasaka 1990). However, sequence analysis of the mtDNA D-loop region directly offers reliable results and has been used in evolutionary studies (Vigilant et al 1989(Vigilant et al , 1991Soodyall et al 1996;Horai et al 1996;Bonatto and Salzano 1997;Starikovskaya et al 1997).…”

Haplotype Trees and Modern Human Origins

“…The strong rejection of the recent out-of-Africa replacement hypothesis is particularly noteworthy, as this hypothesis has dominated much of the discussion of recent human evolution over the last couple of decades (Stringer and Andrews, 1988;Vigilant et al, 1991;Stringer, 2002). Moreover, a recent analysis claimed that the genetic data \clearly" support the out-of-Africa replacement hypothesis (Ray et al, 2005).…”

Inferring Human Demographic Histories of Non-African Populations from Patterns of Allele Sharing

“…The other major hypothesis posits that there was a single major migration out of Africa and that all extant non-African populations are descended from these first migrants. 5,6 (The focus on extant populations here excludes modern human groups that left no present-day descendants, cf. Fu et al, 2015 andLiu et al, 2015 7,8 ).…”