Maria Helena Lartigau Pereira Franco

The Wai Wai Indians of South America: history and genetics

Demographic medical and genetic information was obtained in a population of Carib-speaking Wai Wai Indians living in northern Brazil. At present mortality is low and fertility moderate, with a low variance in offspring number in completed families. Mobility is high, but about two-thirds of the unions are endogamic. Malaria is the main health problem. Phenotype and allele frequencies were obtained for 27 protein genetic systems. Comparison with six other Carib groups indicates closet affinities with another Amazonian tribe, the Arara. Quantification of the intra- and interpopulation genetic diversity in these seven populations indicate that the variation within groups is only slightly lower than the variation between groups. The level of Carib interpopulation diversity, on the other hand, does not differ significantly from that found in 11 Tupi-speaking populations. In accordance with their history of intermarriage with groups which speak slightly different languages, and consider themselves as distinct, the Wai Wai are clearly more diversified at the intrapopulation level than at least three of the six Carib populations with which they were compared.

Electrophoretic protein polymorphisms in Kaingang and Guarani Indians of Southern Brazil

A total of 337 Kaingang and Guarani Indians from two localities were studied in relation to 18 protein genetic loci. In one of the localities, members of these two groups live side by side but show little genetic similarity, emphasizing the influence of cultural factors in the mating behavior of human groups. Integrating the present results with previous ones, it was verified that the genetic relationships among six Kaingang populations do not follow the pattern expected from their geographical distribution. Comparisons made with three other Ge˜‐speaking tribes indicate that the Kaingang did not separate well from them. Most (96%) of the variability in the six polymorphic systems considered occur at the intrapopulational level. Am. J. Hum. Biol. 9:505–512, 1997.

Effect of genetic variation on the fatty acid-binding properties of human serum albumin and proalbumin

In the circulation, non-esterified fatty acids are transported by albumin which also facilitates their removal from donor cells and uptake into receptor cells. We have studied whether genetic variations in the albumin molecule can affect its in vivo fatty acid-binding properties. The fatty acids bound to 25 structurally different variants and to their wildtype counterparts, isolated from heterozygous carriers, were determined gas chromatographically. The variants were proalbumins, albumins with single amino acid substitutions and glycosylated or truncated albumins. In eight cases the total amount bound to the variants was diminished (0.4-0.8-fold), and in seven cases the load was increased to 1.3 or more of normal. Twenty-one fatty acids were quantitated, and for 19 alloalbumins significant deviations from normal were found. Usually, changes in total and individual fatty acid binding were of the same type, but several exceptions to this rule was found. The glycosylated albumin Casebrook showed the largest changes, the total load and the amount of bound palmitate was 8.6 and 14 times, respectively, the normal. The most pronounced changes and the majority of cases of increased binding were caused by molecular changes in domain III. Mutations in domain I, II and the propeptide resulted in smaller effects, if any, and these were often reductions in binding.

The Brazilian Xavante Indians revisited : New protein genetic studies

A total of 94 individuals from the Xavante village of Rio das Mortes were variously studied in relation to 28 protein genetic systems. No variation was observed for 15 of them, in accordance with previous studies. Of the remaining 13, four (Rh, Duffy, acid phosphatase, and GC) showed significant departures from the averages obtained in 32 other South American Indian populations. If studies performed in the 1960s are considered, there is indication that no significant changes in this villages gene pool has occurred in the last 30 years. Comparison with two other Xavante populations included nine systems with variation, and for three of them (MNSs, Rh, and Duffy) significant differences were found. Genetically the Rio das Mortes are closer to the São Marcos than to the Simões Lopes Xavantes. A dendrogram considering 25 genetic systems and 33 South American Indian populations was constructed. There the Xavante were grouped together, in two neighboring clusters, with three other tribes who speak Ge languages, But these clusters also present populations who speak other languages, and the reproducibility of the tree is low. South American Indians, at least with this set of markers, do not seem to be clearly classified into defined subgroups.

Biochemical polymorphisms and phenetic relationships in rodents of the genusCtenomys from Southern Brazil

Protein variation at 20 loci was analyzed by starch gel electrophoresis in population samples ofCtenomys flamarioni, C. torquatus, C. sp., andC. minutus collected in 25 localities of Southern Brazil. Results show that these four species exhibit higher levels of genetic variability (He=0.11–0.17) than those reported for most other fossorial rodents. Estimates of similarity coefficients indicate thatC. minutus andC. sp. (S=0.91) are the closest species, whileC. flamarioni (S=0.77) is the most distant from the others. The data presented here support the hypothesis of a relatively recent disjunction ofC. minutus fromC. sp. Within-species similarity indices are of the same order of magnitude as those found between species. The relatively high levels of heterozygosity observed are not in accordance with the view that subterranean taxa should be less variable than aboveground species due to the uniformity of their environment.

PROTEIN GENETIC STUDIES AMONG THE TUPI-MONDE INDIANS OF THE BRAZILIAN AMAZONIA

A sample of 417 individuals belonging to three Tupi‐Mondé‐speaking tribes (Gavião, Surui, Zoró) were variously studied in relation to 26 genetic protein systems. Previous investigations performed among the Surui in relation to some of these systems were confirmed. The three groups do not depart markedly from the genetic pattern already established for South American Indians and show low inter‐ethnic admixture. When these results are combined with those from 10 other Tupi tribes, two clear geographic groupings (southeastern and northwestern) can be discerned. Using different methods to evaluate the same genetic distance matrices, different patterns of association between the Tupi‐Mondé populations were obtained. The populations are probably too similar among themselves, blurring finer relationships. Am. J. Hum. Biol. 10:711–722, 1998.

22 New Data on the Association between the Glyoxalase I and Haptoglobin Loci

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.

Demography and blood genetics of Argentinian Mapuche Indians

The whole Mapuche Indian community of Blancura Centro was covered by a demographic census, with special attention given to variables of genetic interest. Afterwards a sample of it was investigated in relation to 22 genetic systems. The community can be characterized as a young group, with high fertility, but moderate mortality and endogamy. The index of opportunity for selection is relatively low (0.46). The presence of variation at the ABO and Lutheran loci suggests some non-Indian admixture, calculated as 7% in the sample studied. Unusual findings were the absence of L*NS, low frequency (7%) of L*MS and high frequency (37%) of L*Ns. They also showed low frequencies of P*1 (28%) and DI*a (3%), but high of HP*1 (74%). Similarities, but also differences, were noted with previous results obtained in this tribe in Argentina and Chile.

NEW PROTEIN GENETIC STUDIES IN SIX AMAZONIAN INDIAN POPULATIONS

A total of 732 individuals affiliated with six Amazonian Indian populations were variously studied in relation to 26 protein genetic systems. Eleven of them were found to be monomorphic in these groups, in accordance with previous investigations. Similarities and dissimilarities (the latter involving the Rh, Duffy, haptoglobin and transferrin systems) were observed in relation to earlier investigations in four of these populations (Galibi, Palikour, Mundurucu and Tenharim). A dimeric, cathodal variant of albumin was found among two Galibi subjects, and the fairly common occurrence of CP* ACAY among some South American Indian populations was confirmed. The results in the six populations were compared with those from 29 others. When relationships are searched for among tribes of the same linguistic group, the factor that seems to be most influential is geographical localization, an exception being the pattern observed among the Cayapo subgroups. The latter shows genetic differences of the same level of magnitude as those observed among Ge-speaking tribes.

Albumin genetic variability in South America: Population distribution and molecular studies.

A total of 5,020 individuals living in two southern Brazilian states were screened in relation to albumin types; two variants were found, in Passo Fundo (Nagasaki 2) and Vera Cruz (Tradate 2). Another variant, detected in the northeast, was identified as Porto Alegre 2, which also occurs in other places in Brazil, as well as in India, Pakistan, and Turkey. The results were integrated with those obtained in other studies in South America, yielding a total of 16,941 Amerindians and 23,839 non‐Indian subjects. Molecular and physiological studies performed in some of the variants suggested clues to explain the restricted distribution of albumin Yanomama 2 and the widespread occurrence of albumin Maku. Am. J. Hum. Biol. 11:359–366, 1999.