Polymorphism frequencies of the dopamine transporter gene (DAT1) hypervariable region have been analyzed in a sample of Italian and Ivory Coast individuals. The 3' untranslated region (UTR) of DAT1 includes a variable number of tandem repeats (VNTR) of a 40-bp monomer, ranging from 3 to 13 repeats in Caucasian and African populations. In our sample we found alleles with 3 to 16 repeats, and the most common alleles were the 10-repeat (DAT1*10) and the 9-repeat (DAT1*9) alleles. We also found two rare alleles in the Italian population and four in the Ivory Coast population. For the first time the new allele DAT1*16 is described in the Ivorians. The Ivory Coast population was not in Hardy-Weinberg equilibrium for the DAT1 locus because of a deficit of heterozygote genotypes. The observed heterozygosity of the Ivorian population was half that of the Italians. The lower observed heterozygosity and deviation from Hardy-Weinberg equilibrium could be the result of microevolutionary trends, such as genetic drift and/or inbreeding, acting on the relatively small and isolated population sampled for this study, although some sort of selective pressures acting against the shorter alleles cannot be excluded. This evidence, in association with the reduced polymorphism shown by the DAT1 VNTR compared to other VNTRs, seems to indicate that the DAT1 locus may be under some selective pressure.

In this study, the frequencies of CYP1A1, GSTM1, and GSTT1 gene polymorphisms were determined in 133 healthy individuals from Ouangolodougou, a small rural town situated in the north of the Ivory Coast. As appeared in several published studies, ethnic differences in these frequencies have been found to play an important role in the metabolism of a relevant number of human carcinogens. In the studied sample, the frequencies of Ile/Ile (wild type), Ile/Val (heterozygous variant), and Val/Val (homozygous variant) CYP1A1 genotypes were 0.271, 0.692, and 0.037, respectively. Frequencies of GSTM1 and GSTT1 null genotypes were 0.361 and 0.331, respectively. No significant differences were noted between men and women. In contrast to published data for Africans, CYP1A1 *Val Allele frequency (0.383) was significantly high (p < 0.001) in this specific population. For the GSTT1 null genotype, no differences were found between the studied and other African populations, the contrary to what occurred for the GSTM1 null genotype in relation to Gambia and Egypt.

Distribution of some erythrocyte polymorphisms was investigated in five Northern Côte d'Ivoire ethnic groups. For the ABO blood group system, the frequencies of alleles p, q and r were 0.119, 0.150 and 0.731, respectively, while the frequencies of alleles D and d of the Rh blood group system were 0.726 and 0.274, respectively. These values are consistent with published data, while the high incidence of HbAS genotype could result from microevolutionay trends acting on this relatively small population. No 27-bp Southeast Asian ovalocytosis gene deletion was found in the sample.

The present work attempts to determine the distribution of GSTM1 and GSTT1 genotype and allele frequencies in a sample of northern Italian population, and to examine the age-related association of these polymorphisms. The frequencies of the deleted GSTM1 and GSTT1 genotypes were 0.357 and 0.169, respectively. GSTT1 null-genotype frequency found in this work further confirms data obtained in previous studies of Italian populations, while for GSTM1 deletion our sample showed a significantly lower-frequency value with respect to other Italian and European populations, with exception of the Greek. No significant differences occurred between men and women in the frequency of each gene, which could suggest that, in the studied sample, there were no sex differences in susceptibility to diseases and in detoxifying enzymes such as GSTs. In order to analyze the relationship between GSTT1 and GSTM1 gene polymorphisms and age, the sample was subdivided into four age groups: 1-30 years (n = 101); 31-50 years (n = 160); 51-79 years (n = 144) and 80-100 years (n = 58). This age-related analysis showed a decreasing gradient of GSTs null genotypes between younger and older groups, with the 80-100 age group showing a significantly lower frequency of GSTT1 null, GSTM1 null and GSTT1/GSTM1 double null genotypes with respect to the younger group.

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