RESUMO
Despite their ancient past and high diversity, African populations are the least represented in human population genetic studies. In this study, uniparental markers (mtDNA and Y chromosome) were used to investigate the impact of sociocultural factors on the genetic diversity and inter-ethnolinguistic gene flow in the three major Nigerian groups: Hausa (n = 89), Yoruba (n = 135) and Igbo (n = 134). The results show a distinct history from the maternal and paternal perspectives. The three Nigerian groups present a similar substrate for mtDNA, but not for the Y chromosome. The two Niger-Congo groups, Yoruba and Igbo, are paternally genetically correlated with populations from the same ethnolinguistic affiliation. Meanwhile, the Hausa is paternally closer to other Afro-Asiatic populations and presented a high diversity of lineages from across Africa. When expanding the analyses to other African populations, it is observed that language did not act as a major barrier to female-mediated gene flow and that the differentiation of paternal lineages is better correlated with linguistic than geographic distances. The results obtained demonstrate the impact of patrilocality, a common and well-established practice in populations from Central-West Africa, in the preservation of the patrilineage gene pool and in the affirmation of identity between groups.
Assuntos
Cromossomos Humanos Y , DNA Mitocondrial , Fluxo Gênico , Variação Genética , Feminino , Humanos , Masculino , África Ocidental , População Negra/genética , Cromossomos Humanos Y/genética , DNA Mitocondrial/genética , Genética Populacional , Haplótipos , Herança Paterna , População Africana/genéticaRESUMO
Immigrants from diverse origins have arrived in Paraguay and produced important demographic changes in a territory initially inhabited by indigenous Guarani. Few studies have been performed to estimate the proportion of Native ancestry that is still preserved in Paraguay and the role of females and males in admixture processes. Therefore, 548 individuals from eastern Paraguay were genotyped for three marker sets: mtDNA, Y-SNPs and autosomal AIM-InDels. A genetic homogeneity was found between departments for each set of markers, supported by the demographic data collected, which showed that only 43% of the individuals have the same birthplace as their parents. The results show a sex-biased intermarriage, with higher maternal than paternal Native American ancestry. Within the native mtDNA lineages in Paraguay (87.2% of the total), most haplogroups have a broad distribution across the subcontinent, and only few are concentrated around the Paraná River basin. The frequency distribution of the European paternal lineages in Paraguay (92.2% of the total) showed a major contribution from the Iberian region. In addition to the remaining legacy of the colonial period, the joint analysis of the different types of markers included in this study revealed the impact of post-war migrations on the current genetic background of Paraguay.
Assuntos
Migração Humana , Linhagem , Polimorfismo de Nucleotídeo Único , População/genética , Cromossomos Humanos Y/genética , DNA Mitocondrial/genética , Evolução Molecular , Feminino , Humanos , Masculino , Repetições de Microssatélites , Paraguai , Grupos Raciais/genéticaRESUMO
Most studies on maternal lineages of South America populations are restricted to control region (CR) markers and, for some geographical regions, the number of studied samples does not adequately represent the existing diversity. This is the case of mitochondrial DNA (mtDNA) studies on Paraguay that are limited to two Native ethnic groups. To overcome this deficiency, we analysed the mitogenomes from 105 individuals living in Alto Paraná, the second most populated department of the country. Using the Precision ID mtDNA Whole Genome Panel, the molecule was sequenced on Ion S5. The majority of the haplotypes belong to the Native American lineages A, B, C and D. Analyses of maximum parsimony using mitogenome data retrieved from publications and in The 1000 Genomes Project showed a high number of new native American subclades in Paraguay. Also, none of the haplotypes found in Alto Paraná match the remaining South American samples, which include admixed populations from Colombia, Peru and Ecuador, and natives from Colombia and Ecuador. FST genetic distance analysis showed that the native genetic background of Alto Paraná has an intermediate position between the Amazonian groups and the admixed populations from Peru and Ecuador, supporting the theory about the Amazonian origin of the Tupi-Guarani and, at the same time, showing the influence of other linguistic groups.
Assuntos
DNA Mitocondrial , Genética Populacional , Genoma Mitocondrial , Herança Materna , Análise de Sequência de DNA , Etnicidade/genética , Feminino , Variação Genética , Haplótipos , Humanos , Masculino , Filogenia , América do SulRESUMO
In 1985, a frozen mummy was found in Cerro Aconcagua (Argentina). Archaeological studies identified the mummy as a seven-year-old Inca sacrifice victim who lived >500 years ago, at the time of the expansion of the Inca Empire towards the southern cone. The sequence of its entire mitogenome was obtained. After querying a large worldwide database of mitogenomes (>28,000) we found that the Inca haplotype belonged to a branch of haplogroup C1b (C1bi) that has not yet been identified in modern Native Americans. The expansion of C1b into the Americas, as estimated using 203 C1b mitogenomes, dates to the initial Paleoindian settlements (~18.3 thousand years ago [kya]); however, its internal variation differs between Mesoamerica and South America. By querying large databases of control region haplotypes (>150,000), we found only a few C1bi members in Peru and Bolivia (e.g. Aymaras), including one haplotype retrieved from ancient DNA of an individual belonging to the Wari Empire (Peruvian Andes). Overall, the results suggest that the profile of the mummy represents a very rare sub-clade that arose 14.3 (5-23.6) kya and could have been more frequent in the past. A Peruvian Inca origin for present-day C1bi haplotypes would satisfy both the genetic and paleo-anthropological findings.
Assuntos
DNA Mitocondrial/genética , Genoma Mitocondrial/genética , Indígenas Sul-Americanos , Múmias , Argentina , Criança , DNA Mitocondrial/química , DNA Mitocondrial/classificação , Haplótipos , Humanos , Filogenia , Religião , Análise de Sequência de DNARESUMO
Ancestry informative markers (AIMs) can be useful to infer ancestry proportions of the donors of forensic evidence. The probability of success typing degraded samples, such as human skeletal remains, is strongly influenced by the DNA fragment lengths that can be amplified and the presence of PCR inhibitors. Several AIM panels are available amongst the many forensic marker sets developed for genotyping degraded DNA. Using a 46 AIM Insertion Deletion (Indel) multiplex, we analyzed human skeletal remains of post mortem time ranging from 35 to 60 years from four different continents (Sub-Saharan Africa, South and Central America, East Asia and Europe) to ascertain the genetic ancestry components. Samples belonging to non-admixed individuals could be assigned to their corresponding continental group. For the remaining samples with admixed ancestry, it was possible to estimate the proportion of co-ancestry components from the four reference population groups. The 46 AIM Indel set was informative enough to efficiently estimate the proportion of ancestry even in samples yielding partial profiles, a frequent occurrence when analyzing inhibited and/or degraded DNA extracts.
Assuntos
Osso e Ossos/química , DNA/genética , DNA/isolamento & purificação , Genética Forense/métodos , Genética Forense/organização & administração , Mutação INDEL , Grupos Raciais/genética , DNA/análise , Frequência do Gene/genética , Marcadores Genéticos , Genética Populacional , Técnicas de Genotipagem , Humanos , Reação em Cadeia da Polimerase Multiplex/métodosRESUMO
Only a few genetic studies have been carried out to date in Bolivia. However, some of the most important (pre)historical enclaves of South America were located in these territories. Thus, the (sub)-Andean region of Bolivia was part of the Inca Empire, the largest state in Pre-Columbian America. We have genotyped the first hypervariable region (HVS-I) of 720 samples representing the main regions in Bolivia, and these data have been analyzed in the context of other pan-American samples (>19,000 HVS-I mtDNAs). Entire mtDNA genome sequencing was also undertaken on selected Native American lineages. Additionally, a panel of 46 Ancestry Informative Markers (AIMs) was genotyped in a sub-set of samples. The vast majority of the Bolivian mtDNAs (98.4%) were found to belong to the main Native American haplogroups (A: 14.3%, B: 52.6%, C: 21.9%, D: 9.6%), with little indication of sub-Saharan and/or European lineages; however, marked patterns of haplogroup frequencies between main regions exist (e.g. haplogroup B: Andean [71%], Sub-Andean [61%], Llanos [32%]). Analysis of entire genomes unraveled the phylogenetic characteristics of three Native haplogroups: the pan-American haplogroup B2b (originated â¼21.4 thousand years ago [kya]), A2ah (â¼5.2 kya), and B2o (â¼2.6 kya). The data suggest that B2b could have arisen in North California (an origin even in the north most region of the American continent cannot be disregarded), moved southward following the Pacific coastline and crossed Meso-America. Then, it most likely spread into South America following two routes: the Pacific path towards Peru and Bolivia (arriving here at about â¼15.2 kya), and the Amazonian route of Venezuela and Brazil southwards. In contrast to the mtDNA, Ancestry Informative Markers (AIMs) reveal a higher (although geographically variable) European introgression in Bolivians (25%). Bolivia shows a decreasing autosomal molecular diversity pattern along the longitudinal axis, from the Altiplano to the lowlands. Both autosomes and mtDNA revealed a low impact (1-2%) of a sub-Saharan component in Bolivians.
Assuntos
DNA Mitocondrial , Evolução Molecular , Hispânico ou Latino/genética , Bolívia/etnologia , Marcadores Genéticos , Variação Genética , Genética Populacional , Haplótipos , Humanos , Mutação INDEL , FilogeografiaRESUMO
Allele frequencies and forensic parameters for twelve miniSTR autosomal loci (D10S1248, D14S1434, D22S1045, D4S2364, D2S441, D1S1677, D20S480, D6S2439, D6S1056, D9S1118, D4S2639 and D17S1290) were calculated from a sample of 506 unrelated individuals from the Central-East Region of Argentina. No significant deviations from Hardy-Weinberg expectations were found. Furthermore, comparisons with other previously studied populations were made. These twelve miniSTR markers may help forensic laboratories in solving parentage testing as well as in typing degraded DNA samples.
Assuntos
Genética Populacional , Sequências de Repetição em Tandem , Argentina , Impressões Digitais de DNA , Frequência do Gene , Genótipo , Humanos , Reação em Cadeia da PolimeraseRESUMO
The allelic distribution of seventeen short tandem repeat (STR) loci, together with some parameters of forensic interest were estimated from a sample set of unrelated healthy individuals from six provinces in Argentina (Buenos Aires, Córdoba, Santa Fe, Salta, Entre Ríos and Chaco). All loci of the sample were in agreement with Hardy-Weinberg equilibrium, after Bonferroni correction. The combined discrimination power for these 17 STRs was 0.999999999999999999997, whereas the combined probability of exclusion was 0.99999993. Furthermore, this population was compared to other previously published samples from Argentina, showing significant values in the population differentiation tests.
Assuntos
Frequência do Gene , Genética Populacional , Repetições de Microssatélites/genética , Alelos , Argentina , DNA/genética , DNA/isolamento & purificação , Impressões Digitais de DNA , Genética Forense , Marcadores Genéticos , Genótipo , Geografia , Humanos , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase , Controle de QualidadeRESUMO
In a collaborative work carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG), a polymerase chain reaction multiplex was optimized in order to type ten X-chromosome short tandem repeats (STRs) in a single reaction, including: DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08, and DXS7423. Using this X-decaplex, each 17 of the participating laboratories typed a population sample of approximately 200 unrelated individuals (100 males and 100 females). In this work, we report the allele frequencies for the ten X-STRs in 15 samples from Argentina (Buenos Aires, Córdoba, Río Negro, Entre Ríos, and Misiones), Brazil (São Paulo, Rio de Janeiro, Paraná, and Mato Grosso do Sul), Colombia (Antioquia), Costa Rica, Portugal (Northern and Central regions), and Spain (Galicia and Cantabria). Gene diversities were calculated for the ten markers in each population and all values were above 56%. The average diversity per locus varied between 66%, for DXS7133, and 82%, for DXS6809. For this set of STRs, a high discrimination power was obtained in all populations, both in males (> or =1 in 5 x 10(5)) and females (> or =1 in 3 x 10(9)), as well as high mean exclusion chance in father/daughter duos (> or =99.953%) and in father/mother/daughter trios (> or =99.999%). Genetic distance analysis showed no significant differences between northern and central Portugal or between the two Spanish samples from Galicia and Cantabria. Inside Brazil, significant differences were found between Rio de Janeiro and the other three populations, as well as between São Paulo and Paraná. For the five Argentinean samples, significant distances were only observed when comparing Misiones with Entre Ríos and with Río Negro, the only two samples that do not differ significantly from Costa Rica. Antioquia differed from all other samples, except the one from Río Negro.