Strategies for Sharing Limited Resources among Children and Adolescents in Three Traditional Societies of East Africa: Sociocultural and Genetic Factors.

Egalitarianism, pursuit for equality, and altruism are the most important evolutionarily stable strategies in the human society. This study presents data on the results of economic games for sharing with a potential friend or unfamiliar peer in three ethnic groups of East Africa (Hadza, Iraqw, and Meru). The total sample was 583 children and adolescents; mean age, 13.5 ± 3.1 years. In addition, DNA analysis was carried out and the OXTR gene rs53576 single nucleotide polymorphism was genotyped for 162 Meru individuals. The pronounced individual variability in making decisions on sharing with a potential partner was established. Children and adolescents behaved altruistically towards friends significantly more frequently as compared with strangers. Carriers of the OXTR rs53576 GG variant displayed altruism significantly more frequently both to friends (U = 3376.500, p = 0.047; OR = 3.075, p = 0.032) and to strangers (U = 3478.000, p = 0.025; OR = 3.133, p = 0.007). Significant intergroup differences in egalitarianism, egoism, and altruism were also demonstrated. Data obtained suggest a positive group selection towards altruists.

[The 3'-UTR polymorphism of dopamine transporter gene in hadza and datoga males].

The study of VNTR-polymorphism and the molecular struc ture of 3'-UTR of the dopamine transporter gene (DAT1/SLC6A3) was performed in hadza and datoga males. It was shown that hadza and datoga differed in allele and genotype frequencies. Allele with 9 repeats in 3'-UTR is more common in hadza as well as homozygous genotype DAT19/9. Allele with 10 repeats is more common in datoga as well as homozygous genotype DAT1 10/10. The molecular structure of the DAT alleles with 3, 8 and 12 repeats was determined for the first time. In addition it was found that DAT1 allele with 11 repeats in datoga significantly differed from previously described ones in other populations in repeats type and arrangement. We suggest that variations of the repeats num ber and type in the 3'-UTR of allelic variants may affect the dopamine transporter gene function.

[Polymorphism of 5-HTTLPR and Stin2 loci of the serotonin transporter gene in males of African ethnic populations Hadza and Datoga].

A molecular-genetic study of 5-HTTLPR and the Stin2 loci of the serotonin transporter gene (5-HTTL) in males of the African ethnic populations Hadza and Datoga, which differ in the level of culturally acceptable aggression, was carried out. The distribution of allele and genotype frequencies of these two loci was established. It was shown that the frequency distribution of genotypes and alleles among Hadza and Datoga in the examined samples is practically identical by the VNTR-polymorphism of both loci. However, the Hadza populations, as compared to Datoga, showed a significant (p = 0.006) increase in the frequency of the transcriptionally less active allele L(G) of the 5-HTTLPR locus. For the first time, the structure of the allelic variant of locus Stin2 with eight repetitions (Stin2.8) is described and established for African populations. The test for independence of the frequency distribution of the alleles of the studied loci showed highly significant linkage disequilibrium among Hadza (p << 0.001) and Datoga (p = 0.021). In analysis of the genotype combinations of two loci, it was revealed that thestudied populations differed significantly by the L(A)L(G) 10/12 genotype (p << 0.001). When combining the genotypes, no significant differences between the populations based on their expression activity were identified. We assume that the identified combined genotypes reflect the effects of similar behavioral traits for both populations.

[Molecular genetic polymorphism of androgen receptor gene (AR) in African populations of Hadza and Datoga].

The molecular genetic analysis of the polymorphic variants of the CAG repeat-containing locus of the andro- gen receptor (AR) gene was performed in the populations of Hadza and Datoga. Allele frequency distribution patterns were established. Alleles containing 20-25 repeats were the most abundant in both populations were the. The populations studied were compared with Asians (Han), white Americans, and Africans (Ariaal). Sta- tistically significant difference between populations of Hadza and Datoga in the distribution of the AR allelic variants was demonstrated.