The impact of modern migrations on present-day multi-ethnic Argentina as recorded on the mitochondrial DNA genome

Abstract

BackgroundThe genetic background of Argentineans is a mosaic of different continental ancestries. From colonial to present times, the genetic contribution of Europeans and sub-Saharan Africans has superposed to or replaced the indigenous genetic 'stratum'. A sample of 384 individuals representing different Argentinean provinces was collected and genotyped for the first and the second mitochondrial DNA (mtDNA) hypervariable regions, and selectively genotyped for mtDNA SNPs. This data was analyzed together with additional 440 profiles from rural and urban populations plus 304 from Native American Argentineans, all available from the literature. A worldwide database was used for phylogeographic inferences, inter-population comparisons, and admixture analysis. Samples identified as belonging to hg (hg) H2a5 were sequenced for the entire mtDNA genome.ResultsPhylogenetic and admixture analyses indicate that only half of the Native American component in urban Argentineans might be attributed to the legacy of extinct ancestral Argentineans and that the Spanish genetic contribution is slightly higher than the Italian one. Entire H2a5 genomes linked these Argentinean mtDNAs to the Basque Country and improved the phylogeny of this Basque autochthonous clade. The fingerprint of African slaves in urban Argentinean mtDNAs was low and it can be phylogeographically attributed predominantly to western African. The European component is significantly more prevalent in the Buenos Aires province, the main gate of entrance for Atlantic immigration to Argentina, while the Native American component is larger in North and South Argentina. AMOVA, Principal Component Analysis and hgs/haplotype patterns in Argentina revealed an important level of genetic sub-structure in the country.ConclusionsStudies aimed to compare mtDNA frequency profiles from different Argentinean geographical regions (e.g., forensic and case-control studies) should take into account the important genetic heterogeneity of the country in order to prevent false positive claims of association in disease studies or inadequate evaluation of forensic evidence.

Rapid coastal spread of First Americans: Novel insights from South America's Southern Cone mitochondrial genomes

“…These results for D1g and D1j are concordant with a recent study (Bobillo et al 2010), in which the lineage here termed ''D1g'' was found at an overall frequency of 4.73% in Argentina (almost exclusively in the south, at a local high of 27.7%) and the lineage now termed ''D1j'' at 2.66%. These figures differ only slightly from the ones in another recent report (Catelli et al 2011), in which the frequency of D1g in Argentina was 1.3% and that of D1j 3.9%. For details on database frequencies, see Supplemental Table S4.…”

“…To better evaluate the geographical distribution of the novel haplogroups, we surveyed published and unpublished CR data from a wide range of populations (Ginther et al 1993;Horai et al 1993;Alves-Silva et al 2000;Moraga et al 2000;Lalueza-Fox et al 2001;García-Bour et al 2004;Tajima et al 2004;Cabana et al 2006;Á lvarez-Iglesias et al 2007;Tamm et al 2007;Carvalho et al 2008;Salas et al 2008;Bobillo et al 2010;Catelli et al 2011;Gayà-Vidal et al 2011;Prieto et al 2011;Sans et al 2011;MC Bobillo, unpubl.). This allowed the identification of 103 putative D1g and D1j mtDNAs (Supplemental Table S3).…”

“…However, separate source populations for the eastern and western regions have been questioned due to a previously underestimated variation in eastern South America (Lewis and Long 2008). Much later, the genetic composition of both Americas was heavily influenced by contact with Europeans and the trans-Atlantic slave trade (Salas et al 2004;Mendizabal et al 2008;Catelli et al 2011;Gómez-Carballa et al 2012).…”

Mitochondrial DNA analysis suggests a Chibchan migration into Colombia

“…Research using data from modern populations is complicated by the fact that, although some populations (e.g. that of Venezuela) reveal relatively high frequencies of indigenous haplogroups, many indigenous South American populations have been impacted by significant inflows of European and African genes over the last 500 years (Salas et al 2004, Mendizabal et al 2008, Catelli et al 2011, Gómez-Carballa et al 2012). …”

Genetic analysis of paleo-colombians from Nemocón, Cundinamarca provides insights on the early peopling of northwestern South America

“…A Maximum Likelihood (ML) estimate of Gamma parameter for Site Rates (Gamma distribution), was used to model evolutionary rate differences among sites (5 categories, [+G]: AC=AT=CG=GT, AG=CT) and to estimate nucleotide frequencies. The problem variation located around nucleotide position 16189 is usually associated with the length of heteroplasmy (Catelli, et al 2011); therefore the 16182 and 16183 positions (B2 haplogroup) were ignored to calculate diversity indices, genetic distances, NJ phylogeny, and rates/patterns of nucleotide substitution for the Checua group. (5) (Kirkman 1996, Soper 2015.…”