Interpopulational and intrapopulational genetic diversity of Amerindians as revealed by six variable number of tandem repeats

The allele frequencies of six VNTRs (D1S80, D4S43, ApoB 3' VNTR,von Willebrand factor VNTR-I, DXS52 and DYS19) in 123 Amerindians from five tribes (Arara, Wayana-Apalai, Wayampi, Yanomama and Kayapo) were compared with three other Brazilian populations: Whites, Blacks, and individuals of Japanese extraction. The data clearly distinguished the four populations, and measurements of diversity show a decreasing average heterozygosity from Blacks to Whites, Japanese, and Indians. Seven novel alleles were observed; amongst them, two small DYS19) alleles and a large D4S43 allele occurred only in Indians, and may be useful genetic markers for this population. Other prominent features of the Amerindians were: (1) high frequency of ApoB allele 46; (2) absence of a shorter variant of D4S43 allele 1; (3) high frequency, limited to one tribe, of allele 12 of the von Willebrand VNTR. The study also demonstrated a heterogeneity of the Indian tribes, due to both different allele frequencies and the presence or absence of specific alleles. GST was 0.106 for the five Indian populations, and 0.065 for Whites, Blacks and Japanese, H-S and H-T demonstrated that 11% of the total diversity among Amerindians is caused by interpopulational variability, as compared with 7% for the other three racial groups. In contrast, diversity within each tribe is usually low, as demonstrated by a low average number of alleles per locus. These findings indicate that the study of a small number of tribes may not be representative of the variability of Amerindians, even if a large number of individuals are studied. To capture the whole range of genetic variability of Amerindians, it is necessary to study a large number of populations. The limited genetic diversity thus far observed for Amerindians seems to reflect both a genuine decrease of diversity and a bias caused by the study of limited numbers of tribes.