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.

Genetics, surnames, grandparents' nationalities, and ethnic admixture in Southern Brazil: do the patterns of variation coincide?

A total of 2,708 individuals from the European-derived population of Rio Grande do Sul, divided into seven mesoregions, and of 226 individuals of similar origin from Santa Catarina were studied. Seventeen protein genetic systems, as well as grandparents' nationalities, individuals' surnames, and interethnic admixture were investigated. The alleles which presented the highest and lowest differences were GLO1*2 (16 per cent) and PGD*A (2 per cent), respectively, but in general no significant genetic differences were found among mesoregions. The values observed were generally those expected for individuals of European descent, with the largest difference being a lower prevalence (34-39per cent) of P*1. Significant heterogeneity among mesoregions was observed for the other variables considered, and was consistent with historical records. The Amerindian contribution to the gene pool of European-derived subjects in Rio Grande do Sul was estimated to be as high as 11 per cent. Based on the four data sets, the most general finding was a tendency for a northeast-southwest separation of the populations studied. Seven significant phenotype associations between systems were observed at the 5 per cent level (three at the 0.1 per cent level). Of the latter, the two most interesting (since they were also observed in other studies) were MNSs/Duffy and Rh/ACP.

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. Copyright 1999 Wiley-Liss, Inc.

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.

Protein genetic studies among the Tupi-Mondé 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. © 1998 Wiley-Liss, Inc.

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 village's 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.

Prognostic factors to predict outcome following the administration of hypertonic/hyperoncotic solution in hypovolemic patients.

Hypertonic solutions effectively improve hemodynamic parameters in patients admitted to the emergency room. However, no significant differences in outcome were observed compared with standard isotonic treatment in most previously published studies. This study evaluates pretreatment prognostic factors that predict a beneficial effect of hypertonic solution in patients admitted to the emergency room with hemorrhagic hypovolemia in a prospective double-blind fashion. The patients (n = 212) were randomized upon admission to receive 250 mL intravenous (i.v.) bolus of hypertonic 7.5% NaCl + 6% dextran (HSD, n = 101), or isotonic 0.9% NaCl solutions (IS, n = 111) as the first treatment, followed by standard resuscitation. Pretreatment factors assessed were sex, age, cause of hypovolemia, revised trauma score (RTS), Glasgow index, and mean arterial pressure (MAP) on admission. Both groups were compared for survival at 24 h and 30 days postadmission. Infused volumes were registered. HSD administration significantly increased MAP and reduced i.v. crystalloid infusions to maintain hemodynamic parameters, compared with IS. There was no difference between groups in the number of blood transfusions administered. Overall complication rates in both groups were similar (24%). There was a significant difference (p < .03) in overall (30 days) survival rate between HSD (73%) and IS (64%) groups. The 24 h survival rate was significantly lower in IS (72%) compared with HSD (87%); p < .01. Multivariate analyses showed that RTS and MAP were identified as independent predictors for 24 h survival in the group that received HSD. When evaluated for overall survival rate, hypertonic infusion benefited significantly only patients with MAP < 70 mmHg (p < .01).

High-affinity binding of laurate to naturally occurring mutants of human serum albumin and proalbumin.

Binding of laurate (n-dodecanoate) to genetic variants of albumin or its proprotein and to normal albumin isolated from the same heterozygous carriers was studied by a kinetic dialysis technique at physiological pH. The first stoichiometric association constant for binding to proalbumin Lille (Arg-2-->His) and albumin (Alb) Roma (Glu321-->Lys) was increased to 126% and 136% respectively compared with that for binding to normal albumin, whereas the constant for Alb Maku (Lys541-->Glu) was decreased to 80%. In contrast, normal laurate-binding properties were found for as many as nine other albumin variants with single amino acid substitutions. Because the net charges of all these mutants were different from that of normal albumin, the results suggest that the examples of modified laurate binding are not caused by long-range electrostatic effects. Rather, the three positions mentioned are located close to different binding sites for the fatty acid anion. The most pronounced effect was observed for the glycosylated Alb Casebrook, the binding constant of which was decreased to 20%. Binding to the glycosylated Alb Redhill was also decreased, but to a smaller extent (68%). These decreases in binding are caused by partial or total blocking of the high-affinity site by the oligosaccharides, by the negative charges of the oligosaccharides, and/or by conformational changes induced by these bulky moieties. Laurate binding to two chain-termination mutants (Alb Catania and Alb Venezia) was normal, indicating that the C-terminus of albumin is not important for binding. By using different preparations of normal albumin as controls in the binding experiments, it was also possible to compare the effect of various methods for isolation and defatting on laurate binding.

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.

[Erythrocytic enzymatic systems and their antioxidative potential in pregnant women undergoing labor induction with intracervical PGE2]. / Sistemas enzimáticos eritrocitários e seu potencial antioxidante nas grávidas submetidas a indução do trabalho de parto com PGE2 intracervical.

Our purpose is to correlate, the apgar score of the new-borns from induction of labour (IL) with Prostaglandin E2 (PGE2) endocervical gel, and the oxidative environment of the pregnant woman during labour, studying biochemical markers of the erythrocytes. PGE2 is responsible for the regulation of the vascular response in pregnancy, namely for the vasoconstriction caused by Angitensin II. The production of Prostaglandins in vivo depends on mechanisms related to free radicals of oxygen (FRO). The production of FRO is enhanced in normal pregnancy. We have studied two erythrocytic enzymes and plasmatic concentration of PGE2 before and after the IL. Those enzymes are oxireductases-the transmembrane reductase (RTM) and the metahemoglobin reductase (MHR). Their function is to prevent the effects of the FRO on cellular biomolecules namely the endothelium and the red blood cells. This prevention of oxidative stress can facilitate the deformability of the erythrocytes, so these cells can easily transpose the small vessels and bind the oxygen to the tissues. The activity of those enzymes can be modulated by PGE2 used in the IL. We have not found significant variations on the activity of RTM after IL. The activity of MHR was enhanced with statistical significance, 30 minutes after the induction. This enhancement of activity can be a mechanism to prevent the oxidative stress of the induction of labour.

Genetic studies in three South American black populations.

Twenty-one genetic systems were investigated in three relatively isolated South American Black populations. Unexpected allele frequencies were found in different systems in all populations, suggesting the occurrence of genetic drift and/or founder effects. The estimates of racial admixture indicate 50% to 79% of Black ancestry, with various degrees of White (18%-28%) and Amerindian (3%-32%) ancestry.

Biochemical polymorphisms and phenetic relationships in rodents of the genus Ctenomys from southern Brazil.

Protein variation at 20 loci was analyzed by starch gel electrophoresis in population samples of Ctenomys flamarioni, C. torquatus, C. sp., and C. 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 that C. minutus and C. sp. (S = 0.91) are the closest species, while C. flamarioni (S = 0.77) is the most distant from the others. The data presented here support the hypothesis of a relatively recent disjunction of C. minutus from C. 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.

Reconstructing history: the Amazonian Mura Indians.

We studied demographic characteristics of two Mura Indian villages. Two-hundred six inhabitants of these villages and another population were tested in relation to 30 blood and 4 saliva genetic systems. These groups exhibit high mobility and exogamy rates and high fertility but relatively low mortality and variance in number of children per woman. Hb J Oxford and albumin Maku were observed, and they show high prevalences of GPT*1 and RH*R1 but low of HP*1 compared to other South American Indians. Four electrophoretic saliva systems are reported here for the first time in a predominantly Amerindian group. The amount of polymorphism was more limited than that found in Caucasian, black, and Oriental populations. The Mura are still predominantly Indian (82%) but have African (11%) and Caucasoid (7%) admixture. Using these values, the putative ancestral Mura gene frequencies were assessed. Problems related to quantitative estimations of admixture and the factors that influence the process are discussed.

Amino acid substitutions in albumin variants found in Brazil.

Conventional horizontal starch-gel electrophoresis in four buffer systems and structural studies were performed on four albumin variants, and the findings were compared with similar previous data. Albumins Coari I and Porto Alegre I have a previously unreported amino acid substitution (glutamic acid replaced by lysine at position 358, denoted 358 Glu----Lys). The alteration in albumin Porto Alegre II (501 Glu----Lys) is the same as that found for three alloalbumins of Asiatic origin, designated Vancouver, Birmingham, and Adana. Albumin Oriximiná I has the same exchange as albumin Maku (541 Lys----Glu). Some of these findings can be explained only by the occurrence of independent mutations at the same site in the albumin gene. They also point to a third cluster of mutations in that gene, indicating hypermutability in some of its segments.

Genetic variation within the Tupi linguistic group: new data on three Amazonian tribes.

A total of 505 individuals belonging to four populations of three Brazilian Indian tribes were variously studied in relation to 34 genetic systems, and the results were compared with South American Indian averages and five other Tupi populations. Rare variants (CdE of the Rh system, PGM211-1, Cp A-CAY1, serum cholinesterase2 C5+ and some Gm combinations) were observed with varying prevalences, and the three tribes showed different degrees of departure (28%-40% of differences of 10% or more in gene frequencies) from South American Indian averages. People from two communities who speak the same language and are labelled as belonging to the same tribe (Asurini) showed a large degree of genetic differentiation. Another of the tribes studied (Urubu-Kaapor) link through genetic distance analyses with two other tribes from the north of the continent, forming a distinct microevolutionary unit. These features emphasize the peculiarities of the genetic variation in populations with a hunter-gatherer, rudimentary agriculture type of economy.

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.

Gene flow across tribal barriers and its effect among the Amazonian Içana river Indians.

Demographic information was obtained from 622 individuals of five communities of primarily Baniwa Amerindians living near the Içana river in Brazil. Four of these populations, plus another from the same area, were also studied genetically. The latter investigation included the blood and, in some cases, saliva of 531 subjects, variously tested in relation to 40 genetic systems. Demographically these groups are characterized by young age, high intertribal admixture, low non-Indian admixture, high exogamy but low marital distance and high inbreeding, high fertility but low variance in offspring number, and relatively low mortality. Their gene pool shows a peptidase B variant (PEPB2BAN1) and "private" polymorphism of carbonic anhydrase2 (CA2BAN1) until now observed only among them. Other distinctive characteristics are the low frequencies of LNS (0.08), LNs (0.09), RZ (0.01), RO or r(0.02), ACPA (0.08), GALTD (0.01), and the relatively high prevalences of Gm (0.05) and Gc1 (0.82). TfDchi occurs with a low prevalence (0.01). Genetic distance analysis reveals that the one Baniwa sample by history comprised of minimally admixed individuals is quite similar genetically to the Wapishana, another Arawak-speaking tribe some 900 km to the east, and that the genetic distances between the Baniwa communities reflect the amount of historical admixture in a way that indicates which should be excluded from considerations of intertribal genetic distances. Finally, the genetic relation of the Baniwa to the nearby tribes is examined.

Population structure and blood genetics of the Pacaás Novos Indians of Brazil.

Two communities of relatively recently contacted Brazilian Indians, the Pacaás Novos, have been studied in relation to several demographic parameters and 28 genetic systems. The age and sex distribution, fertility and mortality patterns were not very distinct in the two populations, but they differed markedly in relation to the mating, migration and genetic data (six of the 19 variable loci showed differences higher than 10%). This was interpreted as being the consequence of a fission event, one of the many that may periodically occur, sometimes followed by fusions, in populations at this cultural level. The Pacaás Novos also show some distinctive features when previous genetic studies of South American Indians are reviewed, eight alleles of the variable 19 (LMS, R2, R0, Se, Hp1, Gm1,2;21, Gc1F and PGM1(1)), presenting differences varying between 12%-34% from the average obtained considering these earlier investigations.