Thus, Africans differ from one another slightly more than from Eurasians, and the genetic diversity in Eurasians is largely a subset of that in Africans, supporting the out of Africa model of human evolution. From available data for noncoding autosomal regions (total length = 47,038 bp) and X-linked regions (47,421 bp), we estimated the π-values for autosomal regions to be 0.105, 0.070, 0.069, and 0.097% for Africans, Asians, Europeans, and between Africans and Eurasians, and the corresponding values for X-linked regions to be 0.088, 0.042, 0.053, and 0.082%.
The African diversity estimate is even higher than that between Africans and Eurasians (0.096% ± 0.012%). The average nucleotide diversity (π) for the 50 segments is only 0.061% ± 0.010% among Asians and 0.064% ± 0.011% among Europeans but almost twice as high (0.115% ± 0.016%) among Africans. An analysis of the data suggests that the sampling scheme is adequate for our purpose. We sequenced 50 noncoding DNA segments each ∼500 bp long in 10 Africans, 10 Europeans, and 10 Asians.
Thus, it can reflect better the history of human evolution and can serve as a baseline for understanding the maintenance of SNPs in human populations.
We studied the pattern in noncoding regions, because they are less affected by natural selection than are coding regions. The worldwide pattern of single nucleotide polymorphism (SNP) variation is of great interest to human geneticists, population geneticists, and evolutionists, but remains incompletely understood.
0 kommentar(er)
