New genetic data on Amerindians from the Paraguayan Chaco

New data on 17 blood group and protein genetic systems obtained among the Ayoreo and Lengua Indians of Paraguay are presented. They include the first report on the red cell band-3 protein investigated among South American Indians. This information was integrated with previous results available for these two and four other groups. Five of the six populations reside in the Chaco area, while the sixth was included as an outgroup living elsewhere in Paraguay. Four of the five Chaco tribes exhibit good genetic homogeneity, but the Ayoreo are somewhat different. The results confirm the Chaco as a distinct biological (as well as cultural and economic) region, which should be considered in evaluations of genetic variability among South American Indians

Genetic relationships between amerindian populations of Argentina

A total of 495 individuals from five different Argentinian tribes was examined for variation in 23 blood group and protein genetic systems, and the results were integrated with previous data on some of these systems. These tribes generally present RH * R1, PGM1 * 1, and ACP * A frequencies lower and RH * R2, ESD * 1, and GLO * 1 prevalences higher than those observed in other South American Indian groups. Earlier studies with mitochondrial DNA showed that haplogroup A was present in low frequencies in these tribes, but haplogroup B showed a high prevalence among the Mataco. Average heterozygosities are very similar in the five tribes, while estimates of non-Indian ancestry are generally low. Both the blood group and protein, as well as the mtDNA data sets, divide the five tribes into two groups, and the relationships obtained with the blood group and protein systems are exactly those expected on the basis of geography and language. However, the topology obtained with the mtDNA results was different, possibly due to sampling effects or diverse patterns of exchange between the groups related to sex

Chromosome 17p12-q11 harbors susceptibility loci for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of autoantibodies against intracellular components, the formation of immune complexes, and inflammation in various organs, typically the skin and kidney glomeruli. The etiology of the disease is not well understood but is most likely the result of the interaction between genetic and environmental factors. In order to identify susceptibility loci for SLE, we have performed genome scans with microsatellite markers covering the whole genome in families from Argentina, Italy, and Europe. The results reveal a heterogeneous disease with different susceptibility loci in different family sets. We have found significant linkage to chromosome 17p12-q11 in the Argentine set of families. The maximum LOD score was given by marker D17S1294 in combination with D17S1293, when assuming a dominant inheritance model (Z=3.88). We also analyzed a repeat in the promoter region of the NOS2A gene, a strong candidate gene in the region, but no association was found. The-locus on chromosome 17 has © Springer-Verlag 2004