Publications by authors named "Sergio Avena"

8 Publications

  • Page 1 of 1

Fine-scale genomic analyses of admixed individuals reveal unrecognized genetic ancestry components in Argentina.

PLoS One 2020 16;15(7):e0233808. Epub 2020 Jul 16.

Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.

Similarly to other populations across the Americas, Argentinean populations trace back their genetic ancestry into African, European and Native American ancestors, reflecting a complex demographic history with multiple migration and admixture events in pre- and post-colonial times. However, little is known about the sub-continental origins of these three main ancestries. We present new high-throughput genotyping data for 87 admixed individuals across Argentina. This data was combined to previously published data for admixed individuals in the region and then compared to different reference panels specifically built to perform population structure analyses at a sub-continental level. Concerning the Native American ancestry, we could identify four Native American components segregating in modern Argentinean populations. Three of them are also found in modern South American populations and are specifically represented in Central Andes, Central Chile/Patagonia, and Subtropical and Tropical Forests geographic areas. The fourth component might be specific to the Central Western region of Argentina, and it is not well represented in any genomic data from the literature. As for the European and African ancestries, we confirmed previous results about origins from Southern Europe, Western and Central Western Africa, and we provide evidences for the presence of Northern European and Eastern African ancestries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233808PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365470PMC
September 2020

Genetic admixture patterns in Argentinian Patagonia.

PLoS One 2019 17;14(6):e0214830. Epub 2019 Jun 17.

Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.

As in other Latin American populations, Argentinians are the result of the admixture amongst different continental groups, mainly from America and Europe, and to a lesser extent from Sub-Saharan Africa. However, it is known that the admixture processes did not occur homogeneously throughout the country. Therefore, considering the importance for anthropological, medical and forensic researches, this study aimed to investigate the population genetic structure of the Argentinian Patagonia, through the analysis of 46 ancestry informative markers, in 433 individuals from five different localities. Overall, in the Patagonian sample, the average individual ancestry was estimated as 35.8% Native American (95% CI: 32.2-39.4%), 62.1% European (58.5-65.7%) and 2.1% African (1.7-2.4%). Comparing the five localities studied, statistically significant differences were observed for the Native American and European contributions, but not for the African ancestry. The admixture results combined with the genealogical information revealed intra-regional variations that are consistent with the different geographic origin of the participants and their ancestors. As expected, a high European ancestry was observed for donors with four grandparents born in Europe (96.8%) or in the Central region of Argentina (85%). In contrast, the Native American ancestry increased when the four grandparents were born in the North (71%) or in the South (61.9%) regions of the country, or even in Chile (60.5%). In summary, our results showed that differences on continental ancestry contribution have different origins in each region in Patagonia, and even in each locality, highlighting the importance of knowing the origin of the participants and their ancestors for the correct interpretation and contextualization of the genetic information.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214830PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6576754PMC
February 2020

Ancient DNA reveals temporal population structure within the South-Central Andes area.

Am J Phys Anthropol 2018 08 1;166(4):851-860. Epub 2018 Apr 1.

UBA, CONICET, Instituto Interdisciplinario Tilcara, Centro Universitario Tilcara, FFyL, Tilcara, Jujuy, Y4624AFI, Argentina.

Objectives: The main aim of this work was to contribute to the knowledge of pre-Hispanic genetic variation and population structure among the South-central Andes Area by studying individuals from Quebrada de Humahuaca, North-western (NW) Argentina.

Materials And Methods: We analyzed 15 autosomal STRs in 19 individuals from several archaeological sites in Quebrada de Humahuaca, belonging to the Regional Developments Period (900-1430 AD). Compiling autosomal, mitochondrial, and Y-chromosome data, we evaluated population structure and differentiation among eight South-central Andean groups from the current territories of NW Argentina and Peru.

Results: Autosomal data revealed a structuring of the analyzed populations into two clusters which seemed to represent different temporalities in the Andean pre-Hispanic history: pre-Inca and Inca. All pre-Inca samples fell into the same cluster despite being from the two different territories of NW Argentina and Peru. Also, they were systematically differentiated from the Peruvian Inca group. These results were mostly confirmed by mitochondrial and Y-chromosome analyses. We mainly found a clearly different haplotype composition between clusters.

Discussion: Population structure in South America has been mostly studied on current native groups, mainly showing a west-to-east differentiation between the Andean and lowland regions. Here we demonstrated that genetic population differentiation preceded the European contact and might have been more complex than thought, being found within the South-central Andes Area. Moreover, divergence among temporally different populations might be reflecting socio-political changes occurred in the evermore complex pre-Hispanic Andean societies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajpa.23475DOI Listing
August 2018

Pre-Hispanic Mortuary Practices in Quebrada de Humahuaca (North-Western Argentina): Genetic Relatedness among Individuals Buried in the Same Grave.

Ann Hum Genet 2016 07;80(4):210-20

UBA, CONICET, Instituto Interdisciplinario Tilcara, FFyL, Belgrano 445, CP 4624, Tilcara, Jujuy, Argentina.

Almost all pre-Hispanic societies from Quebrada de Humahuaca (north-western Argentina) buried their defuncts in domestic areas, demonstrating the importance of death and its daily presence among the living. Presumably, the collective graves contained related individuals, a hypothesis that can be tested through the study of ancient DNA. This study analyzes autosomal and uniparental genetic markers in individuals from two archaeological sites in Quebrada de Humahuaca occupied during the Late Formative (1450-1050 BP) and Regional Developments I (1050-700 BP) periods. Mitochondrial and Y-chromosome haplotypes were compared in order to establish possible maternal and paternal relatedness. Genotypes for 15 autosomal STRs were used to calculate pairwise relatedness coefficients and pedigree probabilities. High kinship levels among individuals buried in the same graves were found in both sites. Although only two particular cases were analyzed, these results represent an important contribution to the study of mortuary practices in the region by means of ancient DNA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ahg.12159DOI Listing
July 2016

Population data of 15 autosomal STR markers from Afro-Bolivians of Nor Yungas Province (Bolivia).

Int J Legal Med 2015 May 9;129(3):463-4. Epub 2014 Sep 9.

Sistemática y Evolución, Laboratorio de Biología Molecular, Centro Nacional Patagónico-CONICET, Unidad de Diversidad, Bvd. Brown 2915, Puerto Madryn, Chubut, Argentina,

Allele frequencies and forensic parameters for 15 autosomal loci included in the AmpFlSTR® Identifiler kit were estimated in a sample of 57 unrelated Afro-descendants from Nor Yungas (Bolivia). Buccal swabs samples were obtained from voluntary donors, after consent was given. All loci were in Hardy-Weinberg equilibrium after Bonferroni correction. D21S11 was the most informative locus, while the least discriminating locus was D3S1358. The combined power of discrimination and the combined probability of exclusion were >0.99999999 and >0.99997, respectively. The multidimensional scaling (MDS) plot generated by Rst matrix supported that Afro-Bolivians of Nor Yungas preserved a stronger African descent compared to other admixed Latin American populations. These results amplified the Bolivian databases of autosomal STR loci and may provide a useful tool for human identification tests and population genetic studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00414-014-1080-3DOI Listing
May 2015

Heterogeneity in genetic admixture across different regions of Argentina.

PLoS One 2012 10;7(4):e34695. Epub 2012 Apr 10.

Departamento de Antropología, University of Buenos Aires, Buenos Aires, Argentina.

The population of Argentina is the result of the intermixing between several groups, including Indigenous American, European and African populations. Despite the commonly held idea that the population of Argentina is of mostly European origin, multiple studies have shown that this process of admixture had an impact in the entire Argentine population. In the present study we characterized the distribution of Indigenous American, European and African ancestry among individuals from different regions of Argentina and evaluated the level of discrepancy between self-reported grandparental origin and genetic ancestry estimates. A set of 99 autosomal ancestry informative markers (AIMs) was genotyped in a sample of 441 Argentine individuals to estimate genetic ancestry. We used non-parametric tests to evaluate statistical significance. The average ancestry for the Argentine sample overall was 65% European (95%CI: 63-68%), 31% Indigenous American (28-33%) and 4% African (3-4%). We observed statistically significant differences in European ancestry across Argentine regions [Buenos Aires province (BA) 76%, 95%CI: 73-79%; Northeast (NEA) 54%, 95%CI: 49-58%; Northwest (NWA) 33%, 95%CI: 21-41%; South 54%, 95%CI: 49-59%; p<0.0001] as well as between the capital and immediate suburbs of Buenos Aires city compared to more distant suburbs [80% (95%CI: 75-86%) versus 68% (95%CI: 58-77%), p = 0.01]. European ancestry among individuals that declared all grandparents born in Europe was 91% (95%CI: 88-94%) compared to 54% (95%CI: 51-57%) among those with no European grandparents (p<0.001). Our results demonstrate the range of variation in genetic ancestry among Argentine individuals from different regions in the country, highlighting the importance of taking this variation into account in genetic association and admixture mapping studies in this population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0034695PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3323559PMC
October 2012

[Gene mixture in a population sample from Buenos Aires City].

Medicina (B Aires) 2006 ;66(2):113-8

Sección Antropología Biológica, Instituto de Ciencias Antropológicas, Centro de Genética, Facultades de Filosofía y Letras y Ciencias Veterinarias, Universidad de Buenos Aires.

The aim of this study is to estimate the gene admixture in the population of Buenos Aires City from samples of blood donors, which come from a public health centre (Hospital de Clínicas). These studies were performed on 218 unrelated people, who donated blood during the year 2002. Eight erythrocyte genetic systems and GM/KM allotypes were analysed. A survey to obtain information about place of birth, present residence and genealogical data of the donors was performed. The gene frequencies were determined using a method of maximum likelihood. The genetic admixture was calculated through the ADMIX program (trihibride). The Amerindian and African contributions were 15.8% and 4.3% respectively. These data were compared with those obtained in a previous study performed in a private centre (Hospital Italiano de Buenos Aires) and significant differences were observed, except in the KM system. The results obtained are in concordance with the demographic and historic information of Buenos Aires City.
View Article and Find Full Text PDF

Download full-text PDF

Source
November 2006

African ancestry of the population of Buenos Aires.

Am J Phys Anthropol 2005 Sep;128(1):164-70

Institute of Biological Anthropology, University of Oxford, Oxford OX1 3PS, UK. laura.fejerman@bioanth .ox.ac.uk

The population of Argentina today does not have a "visible" black African component. However, censuses conducted during most of the 19th century registered up to 30% of individuals of African origin living in Buenos Aires city. What has happened to this African influence? Have all individuals of African origin died, as lay people believe? Or is it possible that admixture with the European immigrants made the African influence "invisible?" We investigated the African contribution to the genetic pool of the population of Buenos Aires, Argentina, typing 12 unlinked autosomal DNA markers in a sample of 90 individuals. The results of this analysis suggest that 2.2% (SEM=0.9%) of the genetic ancestry of the Buenos Aires population is derived from Africa. Our analysis of individual admixture shows that those alleles that have a high frequency in populations of African origin tend to concentrate among 8 individuals in our sample. Therefore, although the admixture estimate is relatively low, the actual proportion of individuals with at least some African influence is approximately 10%. The evidence we are presenting of African ancestry is consistent with the known historical events that led to the drastic reduction of the Afro-Argentine population during the second half of the 19th century. However, as our results suggest, this reduction did not mean a total disappearance of African genes from the genetic pool of the Buenos Aires population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajpa.20083DOI Listing
September 2005