High-Resolution RFLP Analysisof Mtdna Variation of Southern Kaduna Asholio and Atakar and their Genetic Relationships to other African Populations

The mtDNA variation of 40 individuals (Asholio and Atakar) from Southern Kaduna, in Northern Nigeria, were examined by high-resolution RFLP analysis. The resulting data were combined with published RFLP haplotype from sub-Saharan African populations and then were subjected to phylogenetic analysis to deduce the evolutionary relationships among them. All of the Asholio and Atakar mtDNA samples were found to belong to the major mtDNA lineage, macrohaplogroup L (defined by aHpaI site at nucleotide position 3592), which is prevalent in sub-Saharan African populations. Additional sets of RFLPs subdivided macrohaplogroup L into two extended haplogroups—L1 and L2—both of which appeared in the Asholio and Atakar. Besides revealing the significant substructure of macrohaplogroup L in African populations, these data showed that the Asholio have one of the most ancient RFLP sublineages observed in African mtDNA and, thus, that they could represent one of the oldest human populations. In addition, the Asholio exhibited a set of related haplotypes that were positioned closest to the root of the human mtDNA phylogeny, suggesting that they, too, represent one of the most ancient African populations. Finally, the overall sequence divergence of 214 African RFLP haplotypes defined in both this and other studies was 0.364%, giving an estimated age, for all African mtDNAs, of 125,500–165,500 years before the present, a date that is concordant with all previous estimates derived from mtDNA and other genetic data, for the time of origin of modern humans in Africa.

Key Words: mtDNA, RFLP, Variation and Genetic relationship