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Latitude-correlated polymorphisms can be due to either selection-driven evolution or gene flow. To discriminate between them, we propose an approach that studies subpopulations springing from a single population that have lived for generations at different latitudes and have had a low genetic admixture. These requirements are fulfilled to a large extent by Ashkenazi and Sephardi Jews. The original population lived at a latitude of 35 degrees N, where the Sephardis still live. The Ashkenazis, however, moved to a latitude of 50 degrees N, starting about 10 centuries ago. The present study examines 3 latitude-correlated polymorphisms: PGP, PGM1, and AHSG. We found that PGP*2 and AHSG*2 alleles most likely underwent selection-driven evolution, but that PGM1*ts allele was not similarly affected. Since temperature might have been considered a reasonable selective factor, we also studied a population living at >800 m above sea level from Aosta Valley (Italy).

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 8-bp-long stretch of DNA is informative for estimating the extent of genetic admixture in sub-Saharan Africans.

The EcoRI, RsaI, and MspI RFLPs (restriction fragment length polymorphisms) of the COL1A2 gene, one of the two genes that encode for the polypeptides of type I collagen, have been studied in four West African and two Asian populations to evaluate their potential effectiveness as anthropological markers. All three RFLPs were in Hardy-Weinberg equilibrium. The comparisons between present data on two of the major human groups and those on Europeans and Amerindians show a considerable heterogeneity for each of the three RFLPs under study. EcoRI, in particular, appears to be highly effective in distinguishing Africans, Europeans, and Asians from each other. As expected, the analysis at the haplotype level considerably improves the discriminating efficiency of these three markers by creating a clear-cut distinction between Tharus and Indonesians, the two Asian populations of the present survey. In fact, even though these two populations exhibit the same frequencies for the RsaI and MspI alleles, the frequency of the MspI(-) allele among the RsaI(-) chromosomes is 0.5 +/- 0.14 in the Indonesian sample and 0 + 0.04 in the Tharu sample.

An extremely low production rate of a polymorphic allele (formally called the mutation rate)--a prerequisite for using the allele as a marker (particularly for anthropogenetic purposes where the alleles must be assumed to be monophyletic)--cannot be taken for granted for alleles of highly polymorphic VNTRs, but a low production rate can be used to identify alleles produced by a single nucleotide substitution. This property was indirectly tested for the (ACT)n COL1A2 (of type I collagen) microsatellite SSTR (degree of heterozygosity H = 0.72) by searching for linkage disequilibria between the SSTR's four common alleles (n = 6, 8, 9, or 10) and three RFLPs of the same gene. A strong linkage disequilibrium between at least three of the four SSTR alleles and two of the three closely linked RFLPs has been demonstrated in a Sardinian population (Italy), a finding that suggests a low production rate of these alleles. Thus it seems that this highly polymorphic system and, by a reasonable extrapolation, other VNTRs with a comparable degree of heterozygosity may be valuable anthropogenetic markers, at least in distinguishing subgroups of a major ethnic group.

190 Punjabis (Hindus and Sikhs) of Chandigarh and 152 Hindus of Jodhpur (Rajasthan) were examined for six genetic markers, four of which (APO C-II, C6, C7 and FXIIIA) were not studied before in Asiatic Indians. For APO C-II and C7 only the common phenotype was found in a total of 229 and 99 subjects, respectively. For the remaining four markers the two samples were pooled since the gene frequency estimates were not significantly different: FXIIIA*2 = 0.205 +/- 0.016; C6*B = 0.366 +/- 0.037; PGM1*2 = 0.247 +/- 0.017; PGD*C = 0.041 +/- 0.008. These data may contribute to evaluate the extent of the Mongoloid genetic admixture into the Caucasoid gene pool of the Punjab and Rajasthan Hindu population.

Gene frequencies for 23 genetic biochemical markers have been determined in one sample of Sherpas and two smaller samples, one of Tibetans living in Nepal and one of 'mixed' Nepalese. Sherpas presented a high GPT1 (0.71) and an appreciable incidence of HbE (about 2%). Variant phenotypes for PGM1, PHI, PepB and C were observed.