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Objective: To investigate the evolutionary and demographic history of the Gaucho, a distinct population of southern Brazil, relating it to their culture, to assess possible parallel continuity. Methods: Six binary polymorphisms, an Alu insertion polymorphism (YAP) and 12 short tandem repeat loci in the non-recombining region of the Y-chromosome, as well as the sequence of the first hypervariable segment (HVS-I) of the mitochondrial DNA (mtDNA) control region were studied in 150 unrelated males born in the Pampa region of Rio Grande do Sul. Results: Comparison of the results with the other Brazilian and Uruguayan populations, as well as with their putative ancestors, indicated a stronger male Spanish influence than that observed elsewhere in Brazil, a former Portuguese colony. Extensive mtDNA analyses of their Amerindian component gave clear indications of the presence there of material from extinct (Charrua), as well as extant (Guarani) tribes. Conclusions: The genetic analyses contributed in a significant way to reveal that the known cultural continuity between pre- and post-Columbian Pampa populations was also accompanied by an extraordinary genetic continuity.

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 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.

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.

Results on 605 patients and 597 controls carefully matched in relation to sex, age, marital status and profession are reported. A higher frequency of nonsecretors, as well as an excess of B and lack of A2 were observed among the filarial patients. Since these differences do not occur in other series, however, their significance is doubtful.

The role of genetic factors in the determination of palmar dermatoglyphic patterns was investigated in a series of 49 MZ and 51 DZ twins, using Spearman's rank correlation and analysis of variance. Both methods indicated that the genetic effect in the distribution of patterns is highest in the interdigital III and lowest in the interdigital IV regions, the hypothenar and thenar showing intermediate values. As for interdigital II, no evaluation of genetic effects was possible using the nonparametric test, but the estimates of genetic variance indicate that inherited factors may play a relatively minor role in the pattern distribution of this area.

A total of 73 sera obtained in two villages of the Kraho Indians of Brazil were tested for nine Ag factors. They were uniformly (x–y+), (a1–d+), (t+z–) and (h–) but showed polymorphism at the cg genetic site, the frequency of Agg being 0.63. Considering all the antigens together, the three arrangements found are not new, but their frequencies are different from those observed in one Caucasian, one Oriental and one African population.

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.

The saliva and milk of 250 parturient women were studied in relation to ABH antigen levels; part of the sample was also investigated for the Lewis (Lea) substance. The levels of A and B are higher in saliva, and those of H and Lea higher in milk. The H average salivary titers presented the relationship 0 > A2 > A1 > B > AB, but these differences were not present in milk. In addition, the salivary levels of A and B are similar in individuals of these groups but B > A in AB persons, and A1 > A2; while in milk A > B in A, B and AB subjects, and A1≈ A2. The amount of Lea substance depends of the ABH secretor status in both secretions; but independently of this difference, the average titers were always higher in milk. Correlation coefficients between the levels observed in the two secretions are statistically significant for the A substance in A persons (0.46), H in B (0.58) and Lea in all subjects tested (0.47). A stepwise multiple regression analysis performed to verify the influence of four genetic and six nongenetic variables in the ABH levels of both fluids indicated only one consistent modifying factor: ABO type.

Hemoglobin Porto Alegre, a2β29Ser→cys has been detected in two individuals in a random survey of 1,369 subjects in Belem, Brazil. Studies of the unrelated families were performed, and apparently neither of these was related to the original family with this abnormality that was detected in Porto Alegre, 2,000 miles to the south. This abnormality has also been reported in a family of Spanish ancestry living in Argentina, suggesting that this rare mutant may be more prevalent in the Iberian Peninsula.

No significant differences were observed on the average number of pregnancies and livebirths, as well as on the frequencies of spontaneous abortions, stillbirths, premature children and those dying be

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.

The saliva and milk of 250 parturient women were studied in relation to ABH antigen levels; part of the sample was also investigated for the Lewis (Lea) substance. The levels of A and B are higher in saliva, and those of H and Lea higher in milk. The H average salivary titers presented the relationship O greater than A2 greater than A1 greater than B greater than AB, but these differences were not present in milk. In addition, the salivary levels of A and B are similar in individuals of these groups but B greater than A in AB persons, and A1 greater than A2; while in milk A greater than B in A, B and AB subjects, and A1 approximately equal to A2. The amount of Lea substance depends of the ABH secretor status in both secretions; but independently of this difference, the average titers were always higher in milk. Correlation coefficients between the levels observed in the two secretions are statistically significant for the A substance in A persons (0.46), H in B (0.58) and Lea in all subjects tested (0.47). A stepwise multiple regression analysis performed to verify the influence of four genetic and six nongenetic variables in the ABH levels of both fluids indicated only one consistent modifying factor: ABO type.