46 research outputs found

    Two ethnic-specific polymorphisms in the human beta pseudogene of hemoglobin

    No full text
    Two polymorphic sites, -107 C --> T and -100 G --> C with respect to the cap site of the human beta pseudogene of the hemoglobin gene, are described. They have been studied in five European, one Indian, two Asian, and two sub-Saharan African populations. The -107 C -->T site turned out to be polymorphic in all five European populations and the Indian population (pooled q = 0.142 +/- 0.018) and in the two Asian populations (pooled q = 0.073 +/- 0.025), but it was monomorphic in the two sub-Saharan populations. On the contrary, the -100 G --> C site was polymorphic in the two sub-Saharan samples (q = 0.093 +/- 0.024), but the variant allele was not found in any of the European, Indian, or Asian samples. Thus this only g-bp-long stretch of DNA is informative for estimating the extent of genetic admixture in sub-Saharan Africans

    Confirmation of the potential usefulness of two human beta globin pseudogene markers to estimate gene flows to and from sub-Saharan Africans

    No full text
    Two polymorphic sites, -107 and -100 with respect to the "cap" site of the human beta globin pseudogene, recently discovered in our laboratory, turned out to have an ethnically complementary distribution. The first site is polymorphic in Europeans, North Africans, Indians (Hindu), and Oriental Asians, and monomorphic in sub-Saharan Africans. Conversely, the second site is polymorphic in sub-Saharan African populations and monomorphic in the aforementioned populations. Here we report the gene frequencies of these two polymorphic sites in nine additional populations (Egyptians, Spaniards, Japanese, Chinese, Filipinos, Vietnamese, Africans from Togo and from Benin, and Pygmies), confirming their ethnospecificity and, through the analysis of these two markers in Oromo and Amhara of Ethiopia (two mixed populations), their usefulness in genetic admixture studies. Moreover, we studied another marker polymorphic in sub-Saharan African populations only, a TaqI restriction fragment length polymorphism located in the same region as the present markers, demonstrating the absence of linkage disequilibrium between it and the -100 site, so that we can exclude that the information they provide is redundant

    Haemoglobin S and haemoglobin C: 'quick but costly' versus 'slow but gratis' genetic adaptations to Plasmodium falciparum malaria.

    No full text
    Haemoglobin S (HbS; beta6Glu-->Val) and HbC (beta6Glu-->Lys) strongly protect against clinical Plasmodium falciparum malaria. HbS, which is lethal in homozygosity, has a multi-foci origin and a widespread geographic distribution in sub-Saharan Africa and Asia whereas HbC, which has no obvious CC segregational load, occurs only in a small area of central West-Africa. To address this apparent paradox, we adopted two partially independent haplotypic approaches in the Mossi population of Burkina Faso where both the local S (S(Benin)) and the C alleles are common (0.05 and 0.13). Here we show that: both C and S(Benin) are monophyletic; C has accumulated a 4-fold higher recombinational and DNA slippage haplotypic variability than the S(Benin) allele (P = 0.003) implying higher antiquity; for a long initial lag period, the C alleles did apparently remain very few. These results, consistent with epidemiological evidences, imply that the C allele has been accumulated mainly through a recessive rather than a semidominant mechanism of selection. This evidence explains the apparent paradox of the uni-epicentric geographic distribution of HbC, representing a 'slow but gratis' genetic adaptation to malaria through a transient polymorphism, compared to the polycentric 'quick but costly' adaptation through balanced polymorphism of HbS

    Biodemography and genetics of the Berba of Benin

    No full text
    Genetic structure of the Berba of Benin was studied on the basis of biodemographic data and ABO, RH, MNS, KEL, JK, FY, ACP1, ADA, AK1, CA2, ESD, GLO1, G6PD, PGD, PGM1 (subtypes and thermostability), PGM2, PGP, SODA, HB alpha, HB beta, HB delta, BF, C3, and HP gene frequencies. Comparisons were carried out with other populations of Benin and of sub-Saharan Africa. Correspondence analysis revealed genetic differentiation among the three main groups of populations who inhabit sub-Saharan Africa: Bushmen-Hottentots, Pygmies, and Negroes. The genetic differentiation of the Negroes in relation to their linguistic affiliation and geographic localization was evident. The first group included the populations belonging to the Bantoid subfamily of the Nigritic linguistic stock living in southern Africa; in the second subcluster the populations of central-eastern Africa were localized, and the third subcluster included the populations living in the West. (C) 1996 Wiley-Liss, Inc
    corecore