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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., COL1A2, one of the two COL1A genes (COL1A1 and COL1A2) that encodes the chains of type I collagen (a trimer of two [Alpha]1 chains and one [Alpha]2 chain), is the [...]

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).sub.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., Up until the late 1980s most of the known codominant alleles [first of blood group antigens, then of electrophoretic or isoelectrofocusing variants of proteins, and finally of restriction fragment length [...]

Sardinians, a population with many distinct anthropogenetic features, has been studied for the COL1A1 and COL1A2 genes at the DNA level for two purposes: to look for new RFLPs (restriction fragment length polymorphisms) and to study the distribution of three known COL1A2 RFLPs (EcoRI, RsaI, MspI) at both the allele and the haplotype levels. None of the eleven enzyme-probe systems examined led to the discovery of a new polymorphism. The following frequency q was found for the less common allele of the three RFLPs: EcoRI, [q.sub.(+)] = 0.178 ± 0.031; Rsal, [q.sub.(-)] = 0.316 ± 0.038; MspI, [q.sub.(-)] = 0.046 ± 0.017. EcoRI turned out to be the most discriminant of the three polymorphisms because the frequency of the (+) allele in Sardinians was about half that estimated for a large homogeneous white sample (0.18 ± 0.03 vs. 0.30 ± 0.01). So far as the haplotype level is concerned, the sample is made up of triplets (parents and child). Therefore all the haplotype frequencies and delta values (degrees of disequilibrium, D) were obtained by direct counting of the unambiguously identified haplotypes rather than being based on their maximum-likelihood estimates. This together with their analytical and detailed presentation makes these data comparable with future findings, provided that the two data sets are presented in a comparable way. At this level the three RFLPs are efficient in distinguishing Sardinians from Calabrians (southern Italy) but not from the central Italian population. The present results, besides adding a further discriminative criterion between Sardinians and Italians (and whites on the whole), identify the complex COL1A2 locus as a valuable anthropogenetic marker., Restriction fragment length polymorphisms (RFLPs) of the two genes encoding the type I collagen polypeptides are turning out to be valuable anthropogenetic markers [for a review see Pepe et al. [...]