Gm and Inv allotypes in French Guiana Indians

Human Gm, Km, and Am allotypes and their molecular characterization: a remarkable demonstration of polymorphism

Human immunoglobulin allotypes are antigenic determinants (or "markers") determined serologically, classically by hemagglutination inhibition, on the human immunoglobulin (IG) heavy and light chains. The allotypes have been identified on the gamma1, gamma2, gamma3, and alpha2 heavy chains (they are designated as G1m, G2m, G3m, and A2m allotypes, respectively), and on the kappa light chain (Km allotypes). Gm-Am allotypes are inherited in fixed combinations, or Gm-Am haplotypes, owing to the linkage of the human IGHC genes (IGHG3, IGHG1, IGHA1, IGHG2, IGHG4, IGHE, and IGHA2 from 5' to 3' in the IGH locus on chromosome 14). Gm and Am allotypes have been one of the most powerful tools in population genetics and very instrumental in molecular characterization of the human IGHC genes (gene conversion, copy number variation, gene order). They represent a major system for understanding immunogenicity of the polymorphic IG chains, in relation with amino acid and conformational changes. The correlation between G3m allotypes and amino acid changes has been possible with the sequencing of many alleles of the IGHG3 gene, from individuals from different populations and with known allotypes. In this chapter, we integrate genetics and sequence data and provide an updated overview of the Gm-Am haplotypes and Km allotypes. We propose, for the first time, a complete elucidation of the G3m allotypes, illustrated by the "IMGT G3m allele butterfly" concept that allows a graphical representation of the G3m alleles (variants of a gene expressing a given set of allotypes). Knowledge of allotypes is important in antibody engineering and humanization of monoclonal antibodies to improve immunotherapy.

Uniparental (mtDNA, Y-chromosome) polymorphisms in French Guiana and two related populations--implications for the region's colonization

Blood samples collected in four Amerindian French Guiana populations (Palikur, Emerillon, Wayampi and Kali'na) in the early 1980s were screened for selected mtDNA and Y-chromosome length polymorphisms, and sequenced for the mtDNA hypervariable segment I (HVS-I). In addition, two other Amerindian populations (Apalaí and Matsiguenga) were examined for the same markers to establish the genetic relationships in the area. Strong dissimilarities were observed in the distribution of the founding Amerindian haplogroups, and significant p-values were obtained from F(ST) genetic distances. Interpopulation similarities occurred mainly due to geography. The Palikur did not show obvious genetic similarity to the Matsiguenga, who speak the same language and live in a region from where they could have migrated to French Guiana. The African-origin admixture observed in the Kali'na probably derives from historical contacts they had with the Bushinengue (Noir Marron), a group of escaped slaves who now lead independent lives in a nearby region. This analysis has identified significant clues about the Amerindian peopling of the North-East Amazonian region.

Genetic studies in French Guiana populations: Synthesis

Twelve blood group and protein systems from a total of 819 individuals from six tribal groups (Apalaí-Wayana, Emerillon, Kaliña, Palikur Wayampi, and Wayana) living in French Guiana and Brazil were compared with each other and integrated with previous results from 17 other South Amerindian populations studied for the same genetic markers. Using correspondence analysis, map methodologies, and maximum linkage cluster analysis developed with the UPGMA method, we attempted to establish the genetic position of these tribes among South American Indians. Peripheral positions for the Emerillon and the Palikur were observed. Ethnohistorical data in French Guiana suggest that a strong founder effect for the former and endogamy for the latter could have generated the genetic differentiation of these two ethnic groups. However, when considered in a wider context, all French Guiana Natives cluster together in an intermediate position as compared with 17 other Amerindian groups studied for the comparison.

Gm and Km allotypes in Wayampi, Wayana and Emerillon Indians from French Guiana

We have studied 506 Amerindians from three French Guiana groups: 194 Wayampi, living in Trois-Sauts, and 100 in the Camopi area; 47 Emerillon also living in the Camopi area and 165 Wayana on the Litani and Maroni rivers. All samples were tested for G1m(1,2,3,17), G3m(5,6,10,11,13,14,15,16,21,24,28) and Km(1) by the classical method of hemaglutination inhibition. The phenotype and haplotype distributions are presented and have been subjected to factorial correspondence analysis. Two Gm haplotypes are common: Gm1,17;21,28, and Gm1,2,17;21,28, but with an important variation in frequency. A rare haplotype, probably the result of a genetic anomaly: Gm1,17;21R,28, is frequent in the Emerillon (17%). These populations show no evidence of Black or Caucasian admixtures.

A new approach for interpreting the genetic diversity in space: 'Mobile Site Method'. Application to Gm haplotype distribution of twenty-seven Amerindian tribes from North and Central America

We present a new approach, called 'Mobile Site Method' (MSM), to the construction of 'genetic similarity maps' more efficient than that described in a preceding paper (Hazout et al. 1991). After building a triangular mesh between the geographical sites, the method consists of moving these locations at each iteration to reduce the overall differences between the geographic and genetic distances. The genetic similarity map, i.e. the final distorted map, allows the interpretation of the genetic diversity of a population set. We have applied this method to the study of Gm immunoglobulin allotypes of twenty-seven Amerindian groups from North and Central America. By a local weighted linear regression, we have reconstituted the distorted contour of America. This representation completes the observations of the sites during the map distortion. In this study, we have defined a large geographical factor in the genetic data (84% of the variability explained), related to a linguistic factor.

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.

GM allotypes in Native Americans: evidence for three distinct migrations across the Bering land bridge

We report the results of typings, for immunoglobulin G allotypes, of 5392 Native Americans from ten samples, the typings having been performed over the last 20 years. Four cultural groups are represented: the Pimans-Pima and Papago; the Puebloans-Zuni and Hopi; the Pai-Walapai; and the Athabascans-Apache and Navajo. The haplotype Gm1;21 has the highest frequency in each population while Gm1,2;21 is polymorphic in all except the Hopi. The Mongoloid marker Gm1;11,13 is found primarily in the Athabascans. The Caucasian haplotype Gm3;5,11,13 is found at polymorphic frequencies in several of the populations but its frequency is very low or absent among nonadmixed individuals. Although Nei's standard genetic distance analysis demonstrates genetic similarity at the Gm and Km loci, the heterogeneity that does exist is consistent both with what is known about the prehistory of Native Americans and traditional cultural categories. When the current Gm distributions are analyzed with respect to the three-migration hypothesis, there are three distinct Gm distributions for the postulated migrants: Gm1;21 and Gm1,2;21 for the Paleo-Indians 16,000 to 40,000 years ago; Gm1;21, Gm1,2;21, and Gm1;11,13 for the second wave of Na-Dene hunters 12,000 to 14,000 years ago; and Gm1;21 and Gm1;11,13 for the Eskimo-Aleut migration 9,000 years ago. The Pimans, Puebloans, and the Pai are descendents of the Paleo-Indians while the Apache and Navajo are the contemporary populations related to the Na-Dene. Finally, the Gm distribution in Amerindians is found to be consistent with a hypothesis of one migration of Paleo-Indians to South American, while the most likely homeland for the three ancestral populations is found to be in northeastern Asia.

Genetic study of the Cuiva Indians of Venezuela

Serum and red cell protein markers were investigated in Cuiva Indians. Our ethnologic studies indicate that the low degree of genetic variability in this population is probably due to genetic drift.

The immunoglobulin allotypes (Gm and Km) of twelve Indian tribes of Central and South America

The Gm and Km immunoglobulin allotypes are presented, for the first time, for six South American Indian tribes (Baniwa, Kanamari, Kraho, Makiritare, Panoa, and Ticuna) and one Central American tribe (Guaymi). Additional allotype information is presented for five previously reported South American tribes (Cayapo, Piaroa, Trio, Xavante and Yanomama). The distributions of the Gm and Km allotypes among all the tribal populations tested to date are reviewed and evidence is presented for the presence of a north (high)-south(low) cline in Km frequency. The wave theory of the populating of the South American continent was tested by an examination of the distribution of six alleles (Gmax;g, Gma;b0,3,t,Dia,Rx,TFDChi, and 6PGDC), absent in some populations but with polymorphic proportions in others. The present, limited, data failed to confirm the theory.