RESUMO
BACKGROUND: Argentinean population is the result of admixture between South Amerindians, Europeans and to a lesser degree, Africans. Since the advent of forensic molecular genetics, the construction of local reference databases became mandatory. Aiming to further extend the technical quality reference database of Argentina, we present herein the allele frequencies for 24 autosomal STRs, including D22S1045, and SE33 (not previously reported for Argentina in STRidER). CONCLUSIONS: Genotypes of 6454 unrelated individuals (3761 males and 2694 females) from 13 out of 23 provinces were analysed. Forensic parameters were calculated for each marker. The observed heterozygosity ranged from 0.661 (TPOX) to 0.941 (SE33). The locus SE33 was revealed to be the most informative marker showing the highest values for PIC (0.955), GD (0.952), TPI (8.455) and PE (0.879). On the other hand, TPOX turned out to be the least informative marker: PIC (0.618), GD (0.669), and PE (0.371). The high number of analyzed individuals allowed detecting low frequency alleles and microvariants in CSF1PO; D16S539 and D21S11 D18S51; PENTA D; PENTA E and at locus D6S1043. METHODS AND RESULTS: This study is the most extensive for Argentina and complements the already reported information concerning the autosomal STRs commonly used in forensic identification. The results were submitted passing STRidER quality control standards (QC), receiving the reference number STR000327 v.2.
Assuntos
Genética Populacional , Repetições de Microssatélites , Masculino , Humanos , Argentina , Repetições de Microssatélites/genética , Frequência do Gene/genética , Impressões Digitais de DNA/métodosRESUMO
Argentina hosts more than 30 Native American groups, who are widely distributed throughout the country. Mataco-Guaycurú speakers settled in the ecoregion of Gran Chaco and represent 26.7% of the extant aboriginal population of the country. To further investigate the genetic attributes of these speakers, we focused our attention on four aboriginal groups, namely, Wichí, Toba, Pilagá and Mocoví, belonging to the Mataco-Guaycurú linguistic group. Our main goal was to evaluate the interrelationships among the groups and the relationships of these groups with admixed urban populations and to assess correspondences between molecular analysis and historical information. A total of 890 samples (282 Native Americans and 608 inhabitants of admixed urban areas) were analysed. Genetic information was gathered from 15 autosomal STRs, 17 Y-STRs, entire mtDNA control region sequences, 24 AIM-SNPs and 46 AIM-DIPs. Native American signatures were detected in 97.9% of mtDNA lineages, 89.1% of Y-haplotypes and 90.3% to 96.9% of autosomal markers. Wichí exhibited the genetic composition with the largest Native American contribution among the groups and a weak signal of gene flow. This work provides extended genetic information of potential interest in the fields of molecular anthropology and forensic genetics.
Assuntos
Indígenas Sul-Americanos/genética , Idioma , Argentina , Feminino , Marcadores Genéticos/genética , Variação Genética/genética , Genética Populacional , Humanos , Masculino , Repetições de Microssatélites/genética , População Urbana/estatística & dados numéricosRESUMO
Historical records suggest that Chiriguano tribe is the result of a genetic admixture event. The process involved the arrival of Guaraní tribesmen descending from Amazonian region of Brazil along with groups of Arawak origin that inhabited the foothill plains of Bolivia. Later they arrived in Argentina at the beginning of the twentieth century. Aiming to test the historical records, we analysed a set of 46 samples collected at San Ramon de la Nueva Orán, Province of Salta, Argentina. A wide set of uni- and biparentally transmitted genetic markers were analysed, including 23 autosomal STRs; 46 AIM-DIPs and 24 AIM-SNPs all located at diverse autosomal chromosome locations; 23 Y-STRs and the entire mtDNA D-Loop sequence. Ancestry informative markers allowed for the detection of a strong Native American component in the genomes (> 94%), while all mtDNA haplotypes showed Native American characteristic motives, and 93% of Y-haplotypes belonged to the Q1a3a Y-haplogroup. The analysis of mitochondrial haplotypes and Y chromosome, although they did not match other populations, revealed a relationship between the Chiriguano and other groups of Guaraní and Arawak origin inhabiting Brazil and Bolivia, confirming, at least in part, the historical records describing the origins of Chiriguano tribal settlements in northwestern Argentina.
Assuntos
Etnicidade/genética , Genética Populacional/métodos , Indígenas Sul-Americanos/genética , Argentina , Bolívia , Brasil , Cromossomos Humanos Y/genética , DNA Mitocondrial/genética , Feminino , Marcadores Genéticos/genética , Haplótipos , Humanos , Masculino , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
Obtaining informative short tandem repeat (STR) profiles from degraded DNA samples is a challenging task usually undermined by locus or allele dropouts and peak-high imbalances observed in capillary electrophoresis (CE) electropherograms, especially for those markers with large amplicon sizes. We hereby show that the current STR assays may be greatly improved for the detection of genetic markers in degraded DNA samples by using long single stranded DNA polynucleotides (ssDNA polynucleotides) as surrogates for PCR primers. These long primers allow a closer annealing to the repeat sequences, thereby reducing the length of the template required for the amplification in fragmented DNA samples, while at the same time rendering amplicons of larger sizes suitable for multiplex assays. We also demonstrate that the annealing of long ssDNA polynucleotides does not need to be fully complementary in the 5' region of the primers, thus allowing for the design of practically any long primer sequence for developing new multiplex assays. Furthermore, genotyping of intact DNA samples could also benefit from utilizing long primers since their close annealing to the target STR sequences may overcome wrong profiling generated by insertions/deletions present between the STR region and the annealing site of the primers. Additionally, long ssDNA polynucleotides might be utilized in multiplex PCR assays for other types of degraded or fragmented DNA, e.g. circulating, cell-free DNA (ccfDNA).
Assuntos
DNA de Cadeia Simples/genética , Repetições de Microssatélites , Polinucleotídeos/genética , Primers do DNA , Reação em Cadeia da Polimerase/métodosRESUMO
Currently, autosomal Short Tandem Repeat (STR) markers represent the method of election in forensic human identification. Commercial kits of most common use nowadays -e.g. PowerPlex®Fusion, Promega Corp.; AmpFlSTR GlobalFiler, Thermofisher scientific; Investigator 24Plex QS,Qiagen-, allow the co-amplification of 23 highly polymorphic STR loci providing a high discrimination power in human identity testing. However, in complex kinship analysis and familial database searches involving distant relationships, additional DNA typing is often required in order to achieve well-founded conclusions. The recently developed kit Investigator® HDplex (Qiagen) co-amplify twelve autosomal STRs markers (D7S1517, D3S1744, D12S391, D2S1360, D6S474, D4S2366, D8S1132, D5S2500, D18S51, D21S2055, D10S2325, SE33), nine of which are not present in the above mentioned kits, providing a set of efficient supplementary markers for human identification purposes. In this study we genotyped a sample of 980 individuals from urban areas of ten Argentinean provinces using the Investigator® HDplex kit, aiming to provide forensic estimates for use in forensic casework and parentage testing in Argentina. We report reference allelic frequency databases for each of the provinces studied as well as for the combined samples. No deviation of Hardy-Weinberg equilibrium was observed. A reasonable discrimination capacity and power of exclusion was estimated which allowed predicting an acceptable forensic behavior of this kit, either to be used as the main STR panel for simple cases or as an auxiliary tool in complex cases. Additionally, population comparison tests showed that the studied samples are relatively homogeneous across the country for these STR set.
Assuntos
Impressões Digitais de DNA , Bases de Dados de Ácidos Nucleicos , Genética Populacional , Repetições de Microssatélites , Argentina , Frequência do Gene , Genótipo , HumanosRESUMO
We developed and validated a total human DNA quantitation technique that simultaneously allows male DNA detection. This assay, called Amel-Y, is a duplex Real Time PCR followed by HRM (high resolution melting) analysis using the intercalating dye SYTO9. Amel-Y duplex produces two amplicons, one for the amelogenin gene (106/112 bp, female/male) and another (84 bp) corresponding to human Y chromosome-specific fragment to detect male DNA. After HRM analysis, two melting peaks differing in 5.3°C-5.5°C are detected if both male and female DNA are present and only one if only female DNA is present. For specificity assessment, the inclusion of high concentrations of bacterial and fungal DNA in the quantitation reactions allowed discarding species cross-reactivity. A set of crime scene evidence from forensic casework has been quantified with commercial kits and compared with Amel-Y duplex. Our method detected male DNA from a concentration of 18 pg/µL and supports autosomal/Y DNA detection ratio up to 200:1. A limitation of the technique is its inability to quantify male and female donnors in a mixed sample. The Amel-Y duplex demonstrated to be an efficient system for quantifying total human DNA being a specific, rapid, sensitive, and cost-effective method suitable for mixed DNA samples and applicable to any field where human DNA quantification is required, such as molecular diagnosis, population genetics, and forensic identification.
Assuntos
Cromossomos Humanos Y/genética , DNA/análise , Genética Forense/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Amelogenina/genética , DNA/genética , Feminino , Humanos , Masculino , Repetições de Microssatélites/genética , Desnaturação de Ácido Nucleico , Especificidade da EspécieRESUMO
Argentinean Patagonia is inhabited by people that live principally in urban areas and by small isolated groups of individuals that belong to indigenous aboriginal groups; this territory exhibits the lowest population density of the country. Mapuche and Tehuelche (Mapudungun linguistic branch), are the only extant Native American groups that inhabit the Argentinean Patagonian provinces of Río Negro and Chubut. Fifteen autosomal STRs, 17 Y-STRs, mtDNA full length control region sequence and two sets of Y and mtDNA-coding region SNPs were analyzed in a set of 434 unrelated individuals. The sample set included two aboriginal groups, a group of individuals whose family name included Native American linguistic root and urban samples from Chubut, Río Negro and Buenos Aires provinces of Argentina. Specific Y Amerindian haplogroup Q1 was found in 87.5% in Mapuche and 58.82% in Tehuelche, while the Amerindian mtDNA haplogroups were present in all the aboriginal sample contributors investigated. Admixture analysis performed by means of autosomal and Y-STRs showed the highest degree of admixture in individuals carrying Mapuche surnames, followed by urban populations, and finally by isolated Native American populations as less degree of admixture. The study provided novel genetic information about the Mapuche and Tehuelche people and allowed us to establish a genetic correlation among individuals with Mapudungun surnames that demonstrates not only a linguistic but also a genetic relationship to the isolated aboriginal communities, representing a suitable proxy indicator for assessing genealogical background.
Assuntos
Cromossomos Humanos Y/genética , DNA Mitocondrial/genética , Genética Populacional , Indígenas Norte-Americanos/genética , Argentina , Haplótipos , Humanos , Indígenas Sul-Americanos/genética , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Numerous studies of human populations in Europe and Asia have revealed a concordance between their extant genetic structure and the prevailing regional pattern of geography and language. For native South Americans, however, such evidence has been lacking so far. Therefore, we examined the relationship between Y-chromosomal genotype on the one hand, and male geographic origin and linguistic affiliation on the other, in the largest study of South American natives to date in terms of sampled individuals and populations. A total of 1,011 individuals, representing 50 tribal populations from 81 settlements, were genotyped for up to 17 short tandem repeat (STR) markers and 16 single nucleotide polymorphisms (Y-SNPs), the latter resolving phylogenetic lineages Q and C. Virtually no structure became apparent for the extant Y-chromosomal genetic variation of South American males that could sensibly be related to their inter-tribal geographic and linguistic relationships. This continent-wide decoupling is consistent with a rapid peopling of the continent followed by long periods of isolation in small groups. Furthermore, for the first time, we identified a distinct geographical cluster of Y-SNP lineages C-M217 (C3*) in South America. Such haplotypes are virtually absent from North and Central America, but occur at high frequency in Asia. Together with the locally confined Y-STR autocorrelation observed in our study as a whole, the available data therefore suggest a late introduction of C3* into South America no more than 6,000 years ago, perhaps via coastal or trans-Pacific routes. Extensive simulations revealed that the observed lack of haplogroup C3* among extant North and Central American natives is only compatible with low levels of migration between the ancestor populations of C3* carriers and non-carriers. In summary, our data highlight the fact that a pronounced correlation between genetic and geographic/cultural structure can only be expected under very specific conditions, most of which are likely not to have been met by the ancestors of native South Americans.
Assuntos
Cromossomos Humanos Y/genética , Haplótipos/genética , Indígenas Sul-Americanos/genética , Repetições de Microssatélites/genética , América Central , Europa (Continente) , Genótipo , Geografia , Humanos , Idioma , Linguística , Masculino , Filogenia , Polimorfismo de Nucleotídeo Único , Grupos Populacionais/genética , América do SulRESUMO
Aiming to detect individuals of Native American maternal or paternal ancestry a rapid screening approach has been developed. Its strategy was based on SNP typing by Real Time PCR (rt-PCR) followed by High Resolution Melting analysis (HRM). After extraction, DNA was quantitated by rt-PCR using commercial kits; samples were then submitted to two multiplex reactions in order to determine the major Native American mtDNA and Y-chromosome haplogroups by HRM. One cocktail included primers flanking nucleotide substitutions that define mtDNA haplogroup C and sub-haplogroups A2, B2, and D1. The other included primers flanking Y-SNPs M3, M269 and U179 that allowed discriminating Q and non-Q haplogroups. In all cases amplicons were <125 nucleotides long in order to increase the peak resolution. The accuracy of the results obtained was established by means of sequencing analysis of the amplicons. The new working-flow here proposed facilitates and speeds-up the screening process that may preclude a detailed sequencing analysis of particular samples, or for further molecular epidemiological investigations in which continental origin influences might be relevant.
Assuntos
Cromossomos Humanos Y , DNA Mitocondrial/genética , Etnicidade/genética , Genética Populacional , Haplótipos , Argentina , Impressões Digitais de DNA , Humanos , Masculino , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Análise de SequênciaRESUMO
A set of 200 samples, 100 males and 100 females, obtained from unrelated Argentinean donors were analyzed using 10 X-STRs-DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS7423, DXS6809, DXS7132, DXS9902 and DXS6789-in order to obtain allele frequencies. Statistical analysis was performed using Powerstats and Arlequin software. The population showed no deviation from Hardy Weinberg equilibrium at all loci analyzed. Allele frequencies were compared with Spanish and Portuguese sample sets showing no statistical significant differences in four of the 10 markers analyzed. The most polymorphic marker was DXS6809 and the high values of combined power of exclusion (99.9993355% in trios and 99.9715450% in duos) reinforce the usefulness of this set of markers for kinship test and human identification.