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A review is made of G6PD population surveys conducted in 4,558 European-derived, 2,484 admixed Black/Indian/White or Black/White, and 10,298 Indian subjects living in South America. Despite the fact that twice more Amerindians than Whites had been examined, no autochtonous variant was found among them, while seven different types (besides the most common Gd*B, Gd*A, Gd*A- and Gd*Med) were observed among the Whites. We also describe two new mutations in the G6PD molecule (Farroupilha, 977 C-->A and Lages, 40 G-->A), bringing the number of mutants characterized to 98. G6PD Lages is the most 5' mutation detected thus far. G6PD Seattle, previously found in the United States and Italy, seems to occur in other European countries and was observed by us in five independent Brazilian families.

Panaquire is a population in Venezuela founded in 1733 by Spaniards from the Canary Islands. In order to define the genetic characteristics of this population the following loci were studied: ABO, RH (Cc, D, Ee), FY, K, JK, HB, ESD, ACP1, HP, TF, CP and ALB. Its sociohistorical features were also investigated. Historic censuses reveal that ethnically Blacks were the most important group in this village during the year 1800 (76%), followed by Amerindians (9%), Mulattoes (5%) and Whites (7%). The results of this analysis show that presently the most important genetic component is of African origin (59%), followed by Amerindian (26%) and Caucasian (15%) contributions. These results suggest that Canarians founded Panaquire, but unfavorable sociopolitical and environmental circumstances, as well as the entrance of former slaves, determined the village's evolution as a Black population. Important gene flow also occurred from Indian settlements, and some admixture with Whites. Our analysis shows once again the importance of handling together genetic and sociocultural variables to have a better interpretation of the evolution of human populations.

A total of 340 individuals living in seven localities of two Brazilian Indian groups (Macushi and Icana River Indians) were studied with respect to coagulation factor XIIIA subtypes. No inter- or intra-tribal differences were observed. The most striking finding was that FXIII*1A, an allele which is fairly common among Asiatic Mongoloids like the Japanese (27%), was nearly absent in these Indians.

A total of 107 Mapuche Indians living in western Argentina were studied with respect to 16 genetic systems. For HLA, there were a few differences in relation to previous studies; and considering the averages observed in 15 other South American tribes, Mapuche Indians showed low values for A2, A9 and C3, but high ones for A28 and B16. This is the first report of the presence (in low frequencies, 1-6%) of alleles C2, C6 and C7, as well as of DR antigens (most frequent alleles DR4 and DR2) in South American Indians. Some peculiar reactions shown by products of locus B suggest the presence of antigens that are characteristic of the Mapuche. As for the other systems, the frequencies of R1 (Rh) and PGM1(1) were lower but those for r (Rh), GLO1 and Hp1 were higher than the averages obtained considering previous studies of this ethnic group. Other salient findings were the variability observed in the PGM2 and C3 systems, and the low prevalence of Bfs.

No association between GLO and Hp was found in three Brazilian samples (153 Whites, 216 Blacks from Porto Alegre and 564 mixed individuals from Aracaju). In a sample of 174 Blacks (settled along the Trombetas river) a moderate (p less than 0.02) association was found, but not of the same kind as that observed by other authors. Population stratification instead of interactions in fitness may explain our findings.

During a paternity test performed in Porto Alegre, Brazil, a rare variant of superoxide dismutase, probably SOD A2, was found in a Caucasian child and the putative father. Studies of 1,700 unrelated white individuals from the same and nearby cities had never disclosed such a variant, which was also absent in 2,480 persons of other ethnic groups living in different regions of Brazil. The presence of this rare phenotype in the child and putative father led to the assignment of a very high probability of paternity to the latter.

10 rare albumin variants found in Brazil have been compared with 6 others, discovered elsewhere, through horizontal starch gel electrophoresis in four buffer systems. Belém V can be clearly distinguished from Naskapi but shows the same mobility as Máku (= Belém III) in two different pHs. Coari II, Manaus I and Porto Alegre II can be separated from all others in three buffer systems. Belém II (= Mexico) and Belém I also show unique patterns, but Coari I, Porto Alegre I and Belém IV could not be distinguished from Santa Ana. The possibly synonymous Belém III-Belém V-Máku should have originated from an Amerindian gene pool, but Coari I-Porto Alegre I-Belém IV-Santa Ana may have a Caucasoid origin.