Differential Structuring of Human Populations for Homologous X and Y Microsatellite Loci

Abstract

The global pattern of variation at the homologous microsatellite loci DYS413 (Yq11) and DXS8174 and DXS8175 (Xp22) was analyzed by examination of 30 world populations from four continents, accounting for more than 1,100 chromosomes per locus. The data showed discordant patterns of among- and within-population gene diversity for the Y-linked and the X-linked microsatellites. For the Y-linked polymorphism, all groups of populations displayed high FST values (the correlation between random haplotypes within subpopulations, relative to haplotypes of the total population) and showed a general trend for the haplotypes to cluster in a population-specific way. This was especially true for sub-Saharan African populations. The data also indicated that a large fraction of the variation among populations was due to the accumulation of new variants associated with the radiation process. Europeans exhibited the highest level of within-population haplotype diversity, whereas sub-Saharan Africans showed the lowest. In contrast, data for the two X-linked polymorphisms were concordant in showing lower FST values, as compared with those for DYS413, but higher within-population variances, for African versus non-African populations. Whereas the results for the X-linked loci agreed with a model of greater antiquity for the African populations, those for DYS413 showed a confounding pattern that is apparently at odds with such a model. Possible factors involved in this differential structuring for homologous X and Y microsatellite polymorphisms are discussed.

Genetic diversity patterns at the human clock gene period 2 are suggestive of population-specific positive selection

“…The mean and the mean square age of a neutral allele with a given frequency in a population of effective size N e ¼ 10 000 30 were obtained using formulas (13) and (14), respectively, as given by Kimura and Ohta. 31 …”

Y-chromosomal evidence of a pastoralist migration through Tanzania to southern Africa

“…The Kenyan Bantu and South African Bantu samples were obtained from the HDGP-Centre d'Etude du Polymorphisme Humain collection. The Khwe (Kxoe) and !Kung samples were collected, with appropriate consent, in Kimberley, Northern Cape Province, South Africa (38). However, these individuals are recent immigrants to the area.…”

Extensive Population Structure in San, Khoe, and Mixed Ancestry Populations from Southern Africa Revealed by 44 Short 5-SNP Haplotypes

“…Various genetic studies published results on "Khoisan" groups (Chen et al, 2000, Tishkoff et al, 2007, Vigilant et al, 1991, Scozzari et al, 1997, Cruciani et al, 2002, Cruciani et al, 2004, Knight et al, 2003, Jobling and Tyler-Smith, 2003, Scozzari et al, 1999, Henn et al, 2008, Underhill et al, 2000, Underhill et al, 2001, Semino et al, 2002, Rosenberg et al, 2005, Li et al, 2008, Tishkoff et al, 2009). These studies, however, were not representative of all the linguistic families and collectively only included two Juspeaking groups, namely, the Ju/'hoansi and the !Xun and one Khoe-speaking group, namely, the Khwe.…”