Francisco R. Carnese

Beta-globin gene cluster haplotypes in the Mapuche Indians of Argentina

Haplotipos derivados de cinco sitios de restricao polimorficos presentes no agrupamento da globina beta foram investigados em 86 cromossomos da populacao mapuche da Argentina. Esses resultados foram analisados em conjunto com os previamente obtidos para dez tribos indigenas brasileiras. Oito haplotipos foram identificados, dos quais os mais frequentes foram o 2 (57%) e o 6 (27%). A presenca do haplotipo 3 em 2% dos cromossomos dos Mapuches e uma evidencia de mistura com individuos de ancestralidade africana. Devido ao alto numero de haplotipos, a heterozigosidade medida pelo indice Gini-Simpson e mais alta nos Mapuches do que nos indios brasileiros. A distribuicao haplotipica nos Mapuches e tambem significativamente diferente da observada nas tribos brasileiras. Essa heterogeneidade poderia ser parcialmente explicada pela mistura com populacoes nao-indigenas.

HLA-DRB1 alleles in four Amerindian populations from Argentina and Paraguay

The major histocompatibility complex (MHC) is one of the biological systems of major polymorphisms. The study of HLA class II variability has allowed the identification of several alleles that are characteristic to Amerindian populations, and it is an excellent tool to define the relations and biological affinities among them. In this work, we analyzed the allelic distribution of the HLA-DRB1 class II locus in four Amerindian populations: Mapuche (n = 34) and Tehuelche (n = 23) from the Patagonian region of Argentina, and Wichi SV (n = 24) and Lengua (n = 17) from the Argentinean and Paraguayan Chaco regions, respectively. In all of these groups, relatively high frequencies of Amerindian HLA-DRB1 alleles were observed (DRB1*0403, DRB1*0407, DRB1*0411, DRB1*0417, DRB1*0802, DRB1*0901, DRB1*1402, DRB1*1406 and DRB1*1602). However, we also detected the presence of non-Amerindian variants in Mapuche (35%) and Tehuelche (22%). We compared our data with those obtained in six indigenous groups of the Argentinean Chaco region and in a sample from Buenos Aires City. The genetic distance dendrogram showed a clear-cut division between the Patagonian and Chaco populations, which formed two different clusters. In spite of their linguistic differences, it can be inferred that the biological affinities observed are in concordance with the geographic distributions and interethnic relations established among the groups studied.

Demography, genetic diversity, and population relationships among Argentinean Mapuche Indians

Fertility, mortality and migration data from four Mapuche Indian communities located along a 215-km NE-SW linear area in the Province of Rio Negro, Argentina, were collated with genetic information furnished by nine blood group systems and by mtDNA haplogroups. The demographic and genetic data indicated a clear dichotomy, which split the four populations into two groups of two. Differing de grees of non-Indian exchanges was probably the main determining factor for this separation. Total genetic variability was very similar i n all groups, and the interpopulational variability accounted for only 10% of the total variability. A low prevalence of the Diego(a) antigen among the Mapuche was confirmed. The fact that significant genetic heterogeneity and population clusters were found in such a small terri torial region attests to the sensitivity of demographic and genetic approaches in unraveling human history.

DISTRIBUCION ALELICA DEL LOCUS HLA-DRB1 EN POBLACIONES NATIVAS AMERICANAS. EVALUACION DE AFINIDADES EVOLUTIVAS INTRA E INTERCONTINENTALES

Carta a los directores de la publicacion en referencia a algunos aspectos de la nota citada.