Population distribution of the human vitamin D binding protein: Anthropological considerations

Abstract

The polymorphism of the serum vitamin D binding protein (DBP) in humans is based on the existence of three common alleles, Gc1F, Gc1S, and Gc2, and 84 rare alleles. The geographical distribution of Gc1F, Gc1S, and Gc2 alleles shows north to south clines, together with a balanced equilibrium between the Gc1F or Gc1S allele frequency and the Gc2 frequency. The distribution of the FST values shows high variability within a geographical area. For European and North Asiatic groups, the FST values are the lowest observed, and the reason may be a long process of homogenization. Aboriginal populations from Australia and New Guinea and groups from both North Africa and South America show the greatest heterogeneity of their allele frequencies. Systematic factors such as genetic drift and selection may account for this distribution. In contrast with the three main DBP alleles, the distribution of the rare alleles corresponds to patterns of human migrations that occurred during prehistoric and historic periods. Thus, the rare mutants are of particular relevance to anthropological and genetical investigations.

Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects

“…Genome-wide association studies have shown that the polymorphism rs7041 and rs4588 are associated with circulating 25(OH)D 3 levels (6,302,475); TT carriers for rs7041 (Gc1S) and AA carriers for rs4588 (Gc2) are associated with lower 25(OH)D 3 levels. The prevalence of these polymorphisms differs between racial groups (97,132,219). Black and Asian populations are far more likely to carry the Gc1f form of DBP, while whites more frequently exhibit the Gc1s form of DBP.…”

Gc and Tf Subtypes in Greece

“…The difference between Greeks and the other European populations is the lower GcIF and Gc2 and the higher Gcls al lele frequencies. The lower Gc2 frequency could be explained by the proposed corre lation of its frequency with different geo graphical factors [Papiha et al, 1982;Constans et al, 1985]. On the other hand to ex plain the geographical distribution of the Gcls and GcIF alleles further data are needed [Constanset al, 1985].…”

A BF subtype “Fb1” is a marker gene of some mongoloid populations

“…As for Mongoloid populations, such specific alleles are typically illustrated by the Di S antigen of the Diego blood group (Layrisse et al, 1955), the Gmab3st haplotype of immunoglobulin heavy chain allotypes (Gin, for review see Matsumoto, 1988), the TFDChi allele of transferrin (for review see Kamboh and Ferrell, 1987), a set of rare mutant alleles of vitamin D binding protein (DBP, initially called groupspecific component, Gc, for review see Constans et al, 1985), and so on. The distribution of the rare variants such as TFDChi or DBP variants informs us anthropological relationship between populations, their exchanges, and their migrations (Constans et al, 1985). Based on occurrence or absence of the BF*Fbl allele, Mongoloids could be divided into two groups, which findings implied that two core populations might have occurred before the differentiation of Mongoloid into various groups.…”

“…Analytical data on the Gm haplotype distribution among various Mongoloids provides an evidence for the occurrence of two distinct populations among paleo-Mongoloid populations of East Asia in the past (Matsumoto, 1988). In addition, Constans et al (1985) deduced from the distributions of seven rare variants at DBP locus that considerable differentiation among Mongoloid populations existed, especially between northern and southern ones during the migration to the Americas. Z2=14.5, p--0.…”