RESUMO
This study aimed to analyze autosomal Alu insertions in three localities from Patagonia Argentina belonging to the Andes region and the coast of the Chubut province. Knowledge of the genetic diversity of these populations, along with the genealogical data, will contribute to better understand historical information, differential migration process and bio-demographic composition of the Central Patagonia region. In order to achieve this objective, 16 autosomal Alu insertion polymorphisms were genotyped: ACE, APO-A1, TPA25, FXIIIB, A25, HS4.32, D1, HS4.69, HS2.43, Sb19.12, Yb8NBC120, Sb19.3, Yb8NBC125, Ya5NBC221, DM, and CD4. Our results showed that the Central Patagonia region presents a complex continental genetic admixture with marked Native American roots (39% ± 1.2), Eurasian (56% ± 1.73) and, to a lesser extent, African (5% ± 1.7). The genetic proximity of the Patagonian samples in relation to groups from Europe and Northern Africa, but with a displacement towards the native communities, constitutes a clear indicator of the differential admixture process that took place in different regions of Argentina. Moreover, genetic differences were observed between Patagonian localities and Bahía Blanca (Central region of Argentina). These observations warned us that population genetic constitution analysis cannot be approached without bearing in mind the regional particularities, which are the result of the different historical, migratory, social-economic and demographic processes that occurs in the country.
Este estudio tiene como objetivo el análisis de las inserciones autosómicas Alu en tres localidades de la Patagonia argentina localizadas en la región andina y costera de la provincia de Chubut. El conocimiento de la diversidad genética de estas poblaciones, junto con los datos genealógicos, contribuirán a una mejor comprensión de la información histórica, los procesos migratorios diferenciales y la composición bio-demográfica de la región central Patagónica. Para alcanzar este objetivo se analizaron 16 polimorfismos autosómicos de inserción Alu: ACE, APO-A1, TPA25, FXIIIB, A25, HS4.32, D1, HS4.69, HS2.43, Sb19.12, Yb8NBC120, Sb19.3, Yb8NBC125, Ya5NBC221, DM y CD4. Nuestros resultados mostraron que la región central Patagónica presenta una mezcla genética continental compleja de marcadas raíces nativo americanas 39% (± 1.2), eurasiáticas 56% (± 1.73) y, en menor medida, africanas 5% (± 1.7). La proximidad genética de las muestras patagónicas a los grupos de Europa y del Norte de África, pero con un mayor desplazamiento hacia las comunidades nativas, constituye un claro indicador del proceso de mezcla diferencial que tuvo lugar en las distintas regiones de la Argentina. Por otra parte, las diferencias genéticas observadas entre las localidades de Patagonia y Bahía Blanca (región central de la Argentina), nos advierten que no puede analizarse la constitución genética de las poblaciones sin tener en cuenta las particularidades regionales, que son el resultado de los diferentes procesos históricos, migratorios, socio-económicos y demográficos que ocurrieron en el interior del país.
RESUMO
The city of Bahía Blanca occupies a strategic place in Argentina south of the Pampean region in the north-east corner of the Patagonia. Since 1828, this city has been the historical and political border between Amerindian lands in the south, and the lands of European colonists. Nowadays, Bahía Blanca is an urban population mainly composed by descendents of immigrants from Spain and other European countries with apparently low admixture with Amerindians. In view of the unexpectedly high Amerindian admixture levels (about 46.7%) suggested by mtDNA data, and protein markers (19.5%), we analyzed a set of 19 Alu polymorphisms (18 autosomal, 1 of Chromosome Y) in a well-documented genealogical sample from Bahía Blanca. The genotyped sample was made up of 119 unrelated healthy individuals whose birth place and grandparent origins were fully documented. According to available genealogical records, the total sample has been subdivided into two groups: Bahía Blanca Original (64 individuals with all 4 gandparents born in Argentina) and Bahía Blanca Mix (55 individuals with one to three grandparents born out of Argentina). Allele frequencies and gene diversity values in Bahía Blanca fit well into the European ranges. Population relationships have been tested for 8 Alu markers, whose variation has been described in several Amerindian and European samples. Reynolds genetic distances underline the significant genetic similarity of Bahía Blanca to Europeans (mean distance 0.044) and their differentiation from Amerindians (0.146). Interestingly enough, when the general sample is divided, Bahía Blanca Original appears slightly closer to Amerindians (0.127) in contrast to Bahía Blanca Mix (0.161). Furthermore, the genetic relationships depicted through a principal components analysis emphasize the relative similarity of Bahía Blanca Original to Amerindians. A thorough knowledge of the sample origins has allowed us to make a subtle distinction of the genetic composition of Bahía Blanca.
Assuntos
Elementos Alu/genética , Variação Genética/genética , Genética Populacional , Indígenas Sul-Americanos/genética , Polimorfismo Genético/genética , Adulto , Argentina , Emigração e Imigração , Europa (Continente)/etnologia , Feminino , Frequência do Gene/genética , Humanos , Indígenas Sul-Americanos/etnologia , Masculino , População UrbanaRESUMO
Interethnic differences in the allele frequencies of CYP2D6, NAT2, GSTM1 and GSTT1 deletions have been documented for Caucasians, Asians, and Africans population. On the other hand, data on Amerindians are scanty and limited to a few populations from southern areas of South America. In this report we analyze the frequencies of 11 allele variants of CYP2D6 and 4 allele variants of NAT2 genes, and the frequency of GSTM1 and GSTT1 homozygous deleted genotypes in a sample of 90 donors representing 8 Native American populations from Argentina and Paraguay, identified as Amerindians on the basis of their geographic location, genealogical data, mitochondrial- and Y-chromosome DNA markers. For CYP2D6, 88.6% of the total allele frequency corresponded to *1, *2, *4 and *10 variants. Average frequencies for NAT2 *4, *5, *6 and *7 alleles were 51.2%, 25%, 6.1%, and 20.1%, respectively. GSTM1 deletion ranged from 20% to 66%, while GSTT1 deletion was present in four populations in less than 50%. We assume that CYP2D6 *2, *4, *10, *14; NAT2 *5, *7 alleles and GSTM1 and GSTT1 *0/*0 genotypes are founder variants brought to America by the first Asian settlers.
Assuntos
Arilamina N-Acetiltransferase/genética , Citocromo P-450 CYP2D6/genética , Frequência do Gene/genética , Glutationa Transferase/genética , Indígenas Norte-Americanos/genética , Alelos , Argentina/etnologia , Sistema Enzimático do Citocromo P-450 , Deleção de Genes , Genótipo , Humanos , Paraguai/etnologia , Polimorfismo GenéticoRESUMO
One-hundred three individuals from two Mongolian, two Siberian, and ten native American populations were studied in relation to a 340-bp sequence from an Alu insertion located in the 3' untranslated region of the LDLR gene. Seven haplotypes have been determined, and haplotype B1 was the most common, accounting for about half the sequences found. In general, diversity values are quite high, about 2.5 times higher than those found in other autosomal Alu sequences. Almost all (93%) of the variability occurs at the intrapopulation level, but the greatest among-group differentiation (6-8%) was found when we grouped in a single population all Native Americans plus Siberian Eskimos and Chukchi and compared them with Mongolians. This result is compatible with earlier mtDNA and Y-chromosome suggestions of a single origin for the first colonizers of the American continent. With this nuclear locus it was not possible to broadly distinguish between Central and South American natives. No evidence of selection or marked demographic changes was obtained with these data.
Assuntos
Regiões 3' não Traduzidas/genética , Elementos Alu/genética , Indígena Americano ou Nativo do Alasca/genética , Frequência do Gene , Variação Genética , Genética Populacional , Polimorfismo de Fragmento de Restrição , Indígena Americano ou Nativo do Alasca/etnologia , Povo Asiático/genética , Geografia , Haplótipos , Humanos , Inuíte/genética , Mongólia/etnologia , Sibéria/etnologiaRESUMO
New data on 17 blood group and protein genetic systems obtained among the Ayoreo and Lengua Indians of Paraguay are presented. They include the first report on the red cell band-3 protein investigated among South American Indians. This information was integrated with previous results available for these two and four other groups. Five of the six populations reside in the Chaco area, while the sixth was included as an outgroup living elsewhere in Paraguay. Four of the five Chaco tribes exhibit good genetic homogeneity, but the Ayoreo are somewhat different. The results confirm the Chaco as a distinct biological (as well as cultural and economic) region, which should be considered in evaluations of genetic variability among South American Indians.
Assuntos
Antígenos de Grupos Sanguíneos/genética , Proteínas Sanguíneas/genética , Variação Genética , Indígenas Sul-Americanos , Alelos , Distribuição de Qui-Quadrado , Frequência do Gene , Haplótipos , Humanos , Método de Monte Carlo , Paraguai , Fenótipo , Polimorfismo GenéticoRESUMO
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.
Assuntos
DNA Mitocondrial/genética , Frequência do Gene , Indígenas Norte-Americanos/genética , Argentina , Teste de Histocompatibilidade , Humanos , Proteínas/genéticaRESUMO
The apolipoprotein E (APOE) polymorphism was investigated in 186 individuals from six South American Indian tribes, and the results integrated with those previously presented for this ethnic group. The three APOE alleles commonly reported in other populations were also observed in South Amerindians with a highly heterogeneous distribution. As in other populations, APOE*3 was the most common allele (51-98%) followed by APOE*4 (2-47%). These two isoforms were identified in all tribes, but APOE*2 was observed among the Wai Wai (2%) and Mataco (4%) only. No previous indications of inter-ethnic admixture were observed among the Wai Wai, but the introduction of this allele among the Mataco through non-Indian sources cannot be excluded.
Assuntos
Apolipoproteínas E/genética , Heterogeneidade Genética , Indígenas Sul-Americanos/genética , Alelos , Argentina , Brasil , Frequência do Gene , Humanos , Polimorfismo GenéticoRESUMO
We report the distribution of the APOB signal peptide polymorphism in 5 native populations of South America: 2 samples of Mataco and 1 sample each of Pilagá and Toba from the Argentinian Chaco and 1 sample of Ache from the Paraguay forest. A randomly selected subsample of a previously studied sample from the Cayapa of Ecuador (Scacchi et al. 1997) was reanalyzed to investigate probable differences attributable to sampling, laboratory techniques, or interobserver error. The polymorphism observed in the signal peptide region of the APOB gene among native populations of South America exhibits the same range of variation found among geographic continental populations, confirming the high genetic heterogeneity of South Amerindians. Extremes in the allele prevalences were found among the Mataco and Ache, populations not far apart geographically. The small differences in genotype and allele frequencies between the subsample of the Cayapa analyzed here and the original Cayapa sample and between the 2 Mataco samples were not statistically significant and most likely were due to sampling error.
Assuntos
Apolipoproteínas B/genética , Variação Genética/genética , Indígenas Sul-Americanos/genética , Polimorfismo Genético/genética , Sinais Direcionadores de Proteínas/genética , Alelos , Argentina , Viés , Frequência do Gene/genética , Heterogeneidade Genética , Genótipo , Humanos , ParaguaiRESUMO
Endemic foci for HTLV-II infection have been identified in several Amerindian populations. To determine HTLV-I and/or HTLV-II infection among Amerindians living in Argentina we studied 454 sera or plasmas from Indians and natives from different areas of our country. All samples were tested by the particle agglutination technique, and positive reactions were confirmed by the immunofluorescence assay (IFA). IFA titration was used to differentiate HTLV-I and HTLV-II antibodies. Twenty-three of 222 samples (10.4%) were found positive among the Tobas Indians; 22 samples were typed as HTLV-II and 1 as HTLV-I. Antibodies for HTLV-I were found in the serum and CSF of three natives from Salta with a TSP diagnosis. No positive samples were found among 96 Mapuche Indians and 133 natives from San Luis. Our results indicate that HTLV-II is endemic among the Tobas Indians. In this study, infection by these retroviruses in Argentinian Amerindians seems to have a marked geographic distribution.