Evolutionary relationships of human populations from an analysis of nuclear DNA polymorphisms

Abstract

The genetic relationships of human populations have been studied by comparing gene frequency data for protein and blood-group loci of different populations. DNA analysis now promises to be more informative since not only do the DNA coding sequences have more variation than their corresponding proteins but, in addition, noncoding DNA sequences display more extensive polymorphism. We have now studied the frequency of a group of closely linked nuclear DNA polymorphisms (haplotypes) in the beta-globin gene cluster of normal (beta A) chromosomes of individuals from eight diverse populations. We have found that all non-African populations share a limited number of common haplotypes whereas Africans have predominantly a different haplotype not found in other populations. Genetic distance analysis based on these nuclear DNA polymorphisms indicates a major division of human populations into an African and a Eurasian group.

Haplotypic relationship between SNP and microsatellite markers at the NOS2A locus in two populations

“…27 This is patently markedly different from the NOS2A data, where intermarker LD is lost from Africans and non-Africans alike. While it is possible that the NOS2A À2.6 microsatellite may have been significantly more diverse than the CD4 microsatellite at the time of human population differentiation, so that non-African populations started with a more divergent set of microsatellite alleles for any given haplotype, non-Africans appear to have arisen from a relatively small ancestral migratory population, 60 whose genetic diversity was limited. 61 Moreover, comparative primate data suggest that NOS2A À2.6 microsatellite arose at the time of gorillas, as it is monomorphic in macaques and orangutans, but polymorphic in gorillas and chimpanzees.…”

Extensive genetic diversity in the HLA class II region of Africans, with a focally predominant allele, DRB1*1304.

“…Molecular analysis of nuclear and mitochondrial DNA has provided evidence that sub-Saharan Africans are the most genetically diverse and distinctive major population grouping (1)(2)(3)(4)(5). This, together with relevant palaeotological data (6), led to the suggestion that Africans were the founding population of modern Homo sapiens (1,2).…”

Characterization of β-globin haplotypes using blood spots from a population-based cohort of newborns with homozygous HbS

“…12 Finally, the genetic variability and linkage disequilibrium around the ␤-globin gene cluster, coupled with the high prevalence of the HbS mutation in many areas of the world, make the ␤-globin gene cluster particularly useful for studies of human evolution. [13][14][15][16][17][18] In addition to its contribution to population genetics, the study of the ␤-globin gene cluster has also proven valuable in the study of disorders that are modified by other genes. Although sickle cell anemia (HbS) is a single-gene disorder, clinical variability among those with the same genotype has been documented extensively.…”