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1.
An Acad Bras Cienc ; 95(suppl 1): e20220052, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36921152

RESUMEN

A complex web of causation is involved in adiposity, including environmental, social and genetic factors. We aimed to investigate associations between genetic factors such as ancestry and single nucleotide polymorphisms, and obesity-related traits in a sampled Brazilian population. A sample of 501 unrelated adults participating in 2013 at the longitudinal Pró-Saúde Study (EPS) in Rio de Janeiro, Brazil was selected. We analysed 46 AIM-InDels (insertion/deletion) as genetic ancestry markers and four single nucleotide polymorphisms located in the genes MC4R (rs17782313), FTO (rs9939609), FAIM2 (rs7138803) and BDNF (rs4074134), previously described as associated with obesity. The selected obesity-related markers were anthropometric parameters such as body mass index, waist circumference and waist-to-hip ratio, and body composition measurements namely body fat percentage, android fat mass and gynoid fat mass. The sample showed greater European ancestry (57.20%), followed by African (28.80%) and lastly Amerindian (14%). Our results suggest that the rs4074134 (BDNF) CC genotype was directly associated with gynoid fat mass, whereas body fat percentage, android fat mass and the anthropometric parameters seem not to be associated with neither ancestry nor the four polymorphisms in this population sample, most likely due to a stronger role of social, behavioural and environmental determinants.


Asunto(s)
Factor Neurotrófico Derivado del Encéfalo , Obesidad , Adulto , Humanos , Factor Neurotrófico Derivado del Encéfalo/genética , Brasil , Obesidad/genética , Obesidad/epidemiología , Genotipo , Índice de Masa Corporal , Polimorfismo de Nucleótido Simple/genética , Genómica , Predisposición Genética a la Enfermedad , Receptor de Melanocortina Tipo 4/genética , Proteínas de la Membrana/genética , Proteínas Reguladoras de la Apoptosis/genética , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética
2.
Int J Legal Med ; 135(5): 1753-1765, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33559001

RESUMEN

In order to determine the population allele frequencies of autosomal STR markers of forensic interest in the Zimbabwean population, we analyzed a sample of 478 individuals from 19 different ethnic groups using the PowerPlex® Fusion 6C Kit (Promega Corp, Madison, Wisconsin). The data obtained were compared among the different Zimbabwean ethnic groups as well as with several African populations to establish whether significant differences exist among them. No significant differences were found among the ethnic groups in Zimbabwe. Statistically significant differences were observed between allele frequencies in Zimbabwe and some other African populations, although FST with neighboring Bantu populations from South and Southeast regions were low (below 0.005 in most single locus comparisons).


Asunto(s)
Población Negra/genética , Etnicidad/genética , Frecuencia de los Genes , Repeticiones de Microsatélite , Análisis de Secuencia de ADN , Femenino , Genética de Población , Humanos , Masculino , Zimbabwe/etnología
3.
Am J Phys Anthropol ; 176(1): 109-119, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34169504

RESUMEN

OBJECTIVES: According to demographic history, Ecuador has experienced shifts in its Native American populations caused by European colonization and the African slave trade. The continuous admixture events among Europeans, Native Americans, and Africans occurred differently in each region of the country, producing a stratified population. Thus, the aim of this study was to investigate the level of genetic substructure in the Ecuadorian Mestizo population. MATERIALS AND METHODS: A total of 377 male and 209 female samples were genotyped for two sets of X-chromosomal markers (32 X-Indels and 12 X-STRs). Population analyses performed included Hardy-Weinberg equilibrium tests, LD analysis, PCA, pairwise FST s, and AMOVA. RESULTS: Significant levels of LD were observed between markers separated by distances of less than 1 cM, as well as between markers separated by distances varying from 10.891 to 163.53 cM. Among Ecuadorian regions, Amazonia showed the highest average R2 value. DISCUSSION: When X-chromosomal and autosomal differentiation values were compared, a sex-biased admixture between European men and Native American and African women was revealed, as well as between African men and Native American women. Moreover, a distinct Native American ancestry was discernible in the Amazonian population, in addition to sex-biased gene flow between Amazonia and the Andes and Pacific coast regions. Overall, these results underline the importance of integrating X chromosome information to achieve a more comprehensive view of the genetic and demographic histories of South American admixed populations.


Asunto(s)
Variación Genética/genética , Genética de Población/métodos , Indígenas Sudamericanos/genética , Antropología Física , Cromosomas Humanos X/genética , Ecuador , Femenino , Humanos , Mutación INDEL/genética , Desequilibrio de Ligamiento/genética , Masculino , Repeticiones de Microsatélite/genética
4.
BMC Evol Biol ; 20(1): 15, 2020 01 29.
Artículo en Inglés | MEDLINE | ID: mdl-31996123

RESUMEN

BACKGROUND: The current Brazilian population is the product of centuries of admixture between intercontinental founding groups. Although previous results have revealed a heterogeneous distribution of mitochondrial lineages in the Northeast region, the most targeted by foreign settlers during the sixteenth century, little is known about the paternal ancestry of this particular population. Considering historical records have documented a series of territorial invasions in the Northeast by various European populations, we aimed to characterize the male lineages found in Brazilian individuals in order to discover to what extent these migrations have influenced the present-day gene pool. Our approach consisted of employing four hierarchical multiplex assays for the investigation of 45 unique event polymorphisms in the non-recombining portion of the Y-chromosome of 280 unrelated men from several Northeast Brazilian states. RESULTS: Primary multiplex results allowed the identification of six major haplogroups, four of which were screened for downstream SNPs and enabled the observation of 19 additional lineages. Results reveal a majority of Western European haplogroups, among which R1b-S116* was the most common (63.9%), corroborating historical records of colonizations by Iberian populations. Nonetheless, FST genetic distances show similarities between Northeast Brazil and several other European populations, indicating multiple origins of settlers. Regarding Native American ancestry, our findings confirm a strong sexual bias against such haplogroups, which represented only 2.5% of individuals, highly contrasting previous results for maternal lineages. Furthermore, we document the presence of several Middle Eastern and African haplogroups, supporting a complex historical formation of this population and highlighting its uniqueness among other Brazilian regions. CONCLUSIONS: We performed a comprehensive analysis of the major Y-chromosome lineages that form the most dynamic migratory region from the Brazilian colonial period. This evidence suggests that the ongoing entry of European, Middle Eastern, and African males in the Brazilian Northeast, since at least 500 years, was significantly responsible for the present-day genetic architecture of this population.


Asunto(s)
Filogenia , Grupos Raciales , Brasil , Cromosomas Humanos Y/genética , Genética de Población , Geografía , Haplotipos/genética , Humanos , Masculino , Polimorfismo de Nucleótido Simple/genética
5.
Int J Legal Med ; 134(5): 1569-1579, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32385594

RESUMEN

Although many genes have been shown to be associated with human pigmentary traits and forensic prediction assays exist (e.g. HIrisPlex-S), the genetic knowledge about skin colour remains incomplete. The highly admixed Brazilian population is an interesting study population for investigation of the complex genotype-phenotype architecture of human skin colour because of its large variation. Here, we compared variants in 22 pigmentary genes with quantitative skin pigmentation levels on the buttock, arm, and forehead areas of 266 genetically admixed Brazilian individuals. The genetic ancestry of each individual was estimated by typing 46 AIM-InDels. The mean proportion of genetic ancestry was 68.8% European, 20.8% Sub-Saharan African, and 10.4% Native American. A high correlation (adjusted R2 = 0.65, p < 0.05) was observed between nine SNPs and quantitative skin pigmentation using multiple linear regression analysis. The correlations were notably smaller between skin pigmentation and biogeographic ancestry (adjusted R2 = 0.45, p < 0.05), or markers in the leading forensic skin colour prediction system, the HIrisPlex-S (adjusted R2 = 0.54, p < 0.05). Four of the nine SNPs, OCA2 rs1448484 (rank 2), APBA2 rs4424881 (rank 4), MFSD12 rs10424065 (rank 8), and TYRP1 1408799 (rank 9) were not investigated as part of the HIrisPlex-S selection process, and therefore not included in the HIrisPlex-S model. Our results indicate that these SNPs account for a substantial part of the skin colour variation in individuals of admixed ancestry. Hence, we suggest that these SNPs are considered when developing future skin colour prediction models.


Asunto(s)
Variación Genética , Polimorfismo de Nucleótido Simple , Pigmentación de la Piel/genética , Población Negra/genética , Brasil/etnología , ADN/genética , Marcadores Genéticos , Técnicas de Genotipaje/instrumentación , Humanos , Pueblos Indígenas/genética , Población Blanca/genética
6.
Am J Phys Anthropol ; 173(3): 437-447, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32856314

RESUMEN

Colombia, located in the north of the South American subcontinent is a country of great interest for population genetic studies given its high ethnic and cultural diversity represented by the admixed population, 102 indigenous peoples and African descent populations. In this study, an analysis of the genetic structure and ancestry was performed based on 46 ancestry informative INDEL markers (AIM-INDELs) and considering the genealogical and demographic variables of 451 unrelated individuals belonging to nine Native American, two African American, and four multiple ancestry populations. Measures of genetic diversity, ancestry components, and genetic substructure were analyzed to build a population model typical of the northernmost part of the South American continent. The model suggests three types of populations: Native American, African American, and multiple ancestry. The results support hypotheses posed by other authors about issues like the peopling of South America and the existence of two types of Native American ancestry. This last finding could be crucial for future research on the peopling of Colombia and South America in that a single origin of all indigenous communities should not be assumed. It then would be necessary to consider other events that could explain their genetic variability and complexity throughout the continent.


Asunto(s)
Población Negra , Genética de Población/métodos , Indígenas Sudamericanos , Antropología Física , Población Negra/genética , Población Negra/estadística & datos numéricos , Colombia , Variación Genética/genética , Humanos , Mutación INDEL/genética , Indígenas Sudamericanos/genética , Indígenas Sudamericanos/estadística & datos numéricos , América del Sur
7.
Int J Legal Med ; 133(5): 1385-1388, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30612323

RESUMEN

X-chromosomal markers can be useful in some forensic cases, where the analysis of the autosomal markers is not conclusive. In this study, a population sample of 500 unrelated individuals born in São Paulo State was characterized for 32 X-InDel markers. No deviations from the Hardy-Weinberg equilibrium were detected, except for MID1361. The 32 X-InDels showed an accumulated power of discrimination of 0.9999999999993 in females and 0.99999993 in males and an exclusion chance of 0.999996 in trios and 0.99995 in duos. São Paulo showed lower genetic distances to the Colombian admixed and European populations than to Native American, Asian, or African populations. Ancestry analysis revealed 41.8% European, 31.6% African, and 26.6% Native American contributions. Segregation analysis was performed in 101 trios, and the mutation rate was estimated to be low.


Asunto(s)
Cromosomas Humanos X/genética , Genética de Población/métodos , Mutación INDEL , Indio Americano o Nativo de Alaska/genética , Población Negra/genética , Brasil/etnología , Familia , Femenino , Marcadores Genéticos , Haplotipos , Humanos , Masculino , Reacción en Cadena de la Polimerasa Multiplex , Tasa de Mutación , Paternidad , Población Blanca/genética
8.
Int J Legal Med ; 132(5): 1313-1315, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29356946

RESUMEN

In this work, the YfilerPlus kit was used to investigate a sample of 258 males from Rio de Janeiro. In addition, the previous database of 760 Yfiler profiles deposited in the YHRD was updated to 1610. YfilerPlus markers showed a high haplotype diversity (0.99997), with only one haplotype shared by two individuals. When only considering the Yfiler markers, the haplotype diversity was slightly lower (0.99976), with 5 haplotypes shared by two individuals and 1 haplotype shared by three individuals. Low genetic distances were found between the Rio de Janeiro and European populations as well as the European/Hispanic American samples.


Asunto(s)
Cromosomas Humanos Y/genética , Etnicidad/genética , Variación Genética , Genética de Población , Repeticiones de Microsatélite , Dermatoglifia del ADN , Haplotipos , Humanos , Masculino , Población Blanca
9.
Hum Genet ; 135(3): 309-26, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26781090

RESUMEN

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The "out-of-Taiwan" model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion.


Asunto(s)
Pueblo Asiatico/genética , ADN Mitocondrial/genética , Genoma Humano , Asia Sudoriental , Cromosomas Humanos Y/genética , Bases de Datos Genéticas , Femenino , Estudios de Asociación Genética , Sitios Genéticos , Humanos , Masculino , Modelos Genéticos , Filogenia , Filogeografía , Polimorfismo de Nucleótido Simple , Reproducibilidad de los Resultados
10.
Int J Legal Med ; 130(3): 679-81, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26076592

RESUMEN

Y chromosome markers have been widely studied due to their various applications in the fields of forensic and evolutionary genetics. In this study, 35 Y-SNPs and 17 Y-STRs were genotyped in 253 males from the State of Espirito Santo, Brazil. A total of 18 haplogroups and 243 haplotypes were detected; the haplogroup and haplotype diversities were 0.7794 and 0.9997, respectively. Genetic distance analysis using the Y-STR data showed no statistically significant differences between Espirito Santo and other admixed populations from Brazil. The classification of paternal lineages based on haplogroups showed a predominant European contribution (85.88%), followed by African (11.37%) and Amerindian (2.75%) contributions.


Asunto(s)
Cromosomas Humanos Y , Etnicidad/genética , Genética de Población , Repeticiones de Microsatélite , Polimorfismo de Nucleótido Simple , Brasil , Dermatoglifia del ADN , Marcadores Genéticos , Genotipo , Haplotipos , Humanos , Masculino
11.
Am J Hum Biol ; 28(5): 671-80, 2016 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-26990174

RESUMEN

OBJECTIVES: The purpose of this study was to genetically characterize the male lineages of people who speak Mirandese, an interesting case of a linguistic relict that can still be found in the municipality of Miranda do Douro, NE Portugal. This region lies within the area of the Leonese dialects, which are remnants of the Romance dialects spoken in the Kingdom of Leon currently grouped in the Astur-Leonese linguistic continuum. We intended to disclose affinities with surrounding populations, namely from Spain where the Astur-Leonese is also spoken. METHODS: Eighty-eight unrelated males (58 from Miranda and 30 from Bragança, the broad Portuguese region where Miranda is located) were genotyped with the combined use of 17 Y chromosome short tandem repeats (Y-STRs) and a high resolution Y chromosome single nucleotide polymorphism (Y-SNPs) strategy. Moreover, 236 males from Miranda and neighboring regions, previously classified as R-M269, were also genotyped. RESULTS: R-P312 was the most frequent haplogroup in the Mirandese, followed by J-12f2.1 and T-M70. The male lineages J-12f2.1 and T-M70 were also well represented, and both were shared with descendants of Sephardic Jews. No signs of diversity reduction were detected. CONCLUSIONS: Mirandese speakers display a Y chromosome gene pool that shows a subtle differentiation from neighboring populations, mainly attributable to the assimilation of lineages ascribed to be of Jewish ancestry. Although not revealing signs of geographic/linguistic isolation, no clear affinities with other Astur-Leonese populations were detected. The results suggest that in Miranda language sharing is not accompanied by significant gene flow between populations from both sides of the political border. Am. J. Hum. Biol. 28:671-680, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Cromosomas Humanos Y/genética , Flujo Génico , Variación Genética , Lenguaje , Geografía , Humanos , Lingüística , Masculino , Repeticiones de Microsatélite/genética , Polimorfismo de Nucleótido Simple/genética , Grupos de Población , Portugal
12.
PLoS Genet ; 9(4): e1003460, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23593040

RESUMEN

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.


Asunto(s)
Cromosomas Humanos Y/genética , Haplotipos/genética , Indígenas Sudamericanos/genética , Repeticiones de Microsatélite/genética , América Central , Europa (Continente) , Genotipo , Geografía , Humanos , Lenguaje , Lingüística , Masculino , Filogenia , Polimorfismo de Nucleótido Simple , Grupos de Población/genética , América del Sur
13.
Hum Genet ; 134(9): 1013-27, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26188410

RESUMEN

The Great Lakes lie within a region of East Africa with very high human genetic diversity, home of many ethno-linguistic groups usually assumed to be the product of a small number of major dispersals. However, our knowledge of these dispersals relies primarily on the inferences of historical, linguistics and oral traditions, with attempts to match up the archaeological evidence where possible. This is an obvious area to which archaeogenetics can contribute, yet Uganda, at the heart of these developments, has not been studied for mitochondrial DNA (mtDNA) variation. Here, we compare mtDNA lineages at this putative genetic crossroads across 409 representatives of the major language groups: Bantu speakers and Eastern and Western Nilotic speakers. We show that Uganda harbours one of the highest mtDNA diversities within and between linguistic groups, with the various groups significantly differentiated from each other. Despite an inferred linguistic origin in South Sudan, the data from the two Nilotic-speaking groups point to a much more complex history, involving not only possible dispersals from Sudan and the Horn but also large-scale assimilation of autochthonous lineages within East Africa and even Uganda itself. The Eastern Nilotic group also carries signals characteristic of West-Central Africa, primarily due to Bantu influence, whereas a much stronger signal in the Western Nilotic group suggests direct West-Central African ancestry. Bantu speakers share lineages with both Nilotic groups, and also harbour East African lineages not found in Western Nilotic speakers, likely due to assimilating indigenous populations since arriving in the region ~3000 years ago.


Asunto(s)
Población Negra/genética , ADN Mitocondrial/genética , Variación Genética , Humanos , Filogenia , Filogeografía , Análisis de Componente Principal , Uganda
14.
BMC Genet ; 16: 55, 2015 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-26018448

RESUMEN

BACKGROUND: One of the most important dietary shifts underwent by human populations began to occur in the Neolithic, during which new modes of subsistence emerged and new nutrients were introduced in diets. This change might have worked as a selective pressure over the metabolic pathways involved in the breakdown of substances extracted from food. Here we applied a candidate gene approach to investigate whether in populations with different modes of subsistence, diet-related genetic adaptations could be identified in the genes AGXT, PLRP2, MTRR, NAT2 and CYP3A5. RESULTS: At CYP3A5, strong signatures of positive selection were detected, though not connected to any dietary variable, but instead to an environmental factor associated with the Tropic of Cancer. Suggestive signals of adaptions that could indeed be connected with differences in dietary habits of populations were only found for PLRP2 and NAT2. Contrarily, the demographic history of human populations seemed enough to explain patterns of diversity at AGXT and MTRR, once both conformed the evolutionary expectations under selective neutrality. CONCLUSIONS: Accumulated evidence indicates that CYP3A5 has been under adaptive evolution during the history of human populations. PLRP2 and NAT2 also appear to have been modelled by some selective constrains, although clear support for that did not resist to a genome wide perspective. It is still necessary to clarify which were the biological mechanisms and the environmental factors involved as well as their interactions, to understand the nature and strength of the selective pressures that contributed to shape current patterns of genetic diversity at those loci.


Asunto(s)
Adaptación Biológica/genética , Dieta , Estudios de Asociación Genética , Estilo de Vida , Alelos , Evolución Biológica , Citocromo P-450 CYP3A/genética , Ferredoxina-NADP Reductasa/genética , Frecuencia de los Genes , Humanos , Desequilibrio de Ligamiento , Lipasa/genética , Sitios de Carácter Cuantitativo , Selección Genética , Transaminasas/genética
15.
Int J Legal Med ; 129(4): 673-80, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24878616

RESUMEN

For the correct evaluation of the weight of genetic evidence in a forensic context, databases must reflect the structure of the population, with all possible groups being represented. Countries with a recent history of admixture between strongly differentiated populations are usually highly heterogeneous and sub-structured. Bolivia is one of these countries, with a high diversity of ethnic groups and different levels of admixture (among Native Americans, Europeans and Africans) across the territory. For a better characterization of the male lineages in Bolivia, 17 Y-STR and 42 Y-SNP loci were genotyped in samples from La Paz and Chuquisaca. Only European and Native American Y-haplogroups were detected, and no sub-Saharan African chromosomes were found. Significant differences were observed between the two samples, with a higher frequency of European lineages in Chuquisaca than in La Paz. A sample belonging to haplogroup Q1a3a1a1-M19 was detected in La Paz, in a haplotype background different from those previously found in Argentina. This result supports an old M19 North-south dispersion in South America, possibly via two routes. When comparing the ancestry of each individual assessed through his Y chromosome with the one estimated using autosomal AIMs, (a) increased European ancestry in individuals with European Y chromosomes and (b) higher Native American ancestry in the carriers of Native American Y-haplogroups were observed, revealing an association between autosomal and Y-chromosomal markers. The results of this study demonstrate that a sub-structure does exist in Bolivia at both inter- and intrapopulation levels, a fact which must be taken into account in the evaluation of forensic genetic evidence.


Asunto(s)
Cromosomas Humanos Y , Genética de Población , Haplotipos , Repeticiones de Microsatélite , Grupos Raciales/genética , Bolivia , Dermatoglifia del ADN , ADN Mitocondrial/genética , Genotipo , Humanos , Masculino , Polimorfismo de Nucleótido Simple
16.
Int J Legal Med ; 128(1): 19-25, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23665814

RESUMEN

Various strategies for analysing SNP markers and genotyping have been published with the goal of obtaining informative profiles from biological samples that contain only small amounts of template and/or degraded DNA. In this study, a multiplex assay of 52 autosomal single-nucleotide polymorphisms (SNPs) was used to analyse 438 individuals from urban populations from different regions of Colombia, as well as a sample of 50 Native American individuals of the Pastos ethnic group from Nariño. To determine if significant differences in these 52 SNPs exist between the distinct regions of Colombia, genetic distance and admixture analyses were performed based on the available data for 17 different Colombian population groups and for population groups from Africa, Europe and America. The results demonstrate significant differences between the populations from the Southwest Andean, Central-West Andean, Central-East Andean, Orinoquian and northern Colombian Pacific Coast regions. Most of the regions exhibited a European and Native American admixture. One exception is the population from the region of Chocó (on the northern Pacific Coast), which exhibits a high proportion of African admixture (54 %). From the observed genetic backgrounds, it is possible to conclude that a single reference database for the entire country would not be suitable for forensic purposes. The allele frequencies and the forensically relevant parameters were calculated for all of the markers in each Colombian region with significant values for the combined matching probability (power of discrimination ≥0.99999999999999990) and the combined probability of exclusion (≥0.9990) in trios that were obtained from all of the population groups.


Asunto(s)
Dermatoglifia del ADN/métodos , Etnicidad/genética , Genética Forense/métodos , Marcadores Genéticos/genética , Genética de Población , Genotipo , Polimorfismo de Nucleótido Simple/genética , Colombia , Comparación Transcultural , Frecuencia de los Genes , Variación Genética/genética , Humanos , Valor Predictivo de las Pruebas , Probabilidad
17.
Ann Hum Biol ; 41(5): 453-9, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24215508

RESUMEN

OBJECTIVES: To determine the African, European and Native-American paternal contributions in genetic samples from the Department of Bolivar (Colombia) with the aims of establishing (1) possible population substructures, and (2) the proportion of biological African heritage in admixed populations of European, Amerindian, and African descent. METHODS: Y-SNPs were typed in samples from six communities, including Palenque (renowned for its African linguistic and cultural heritage). RESULTS: Findings reveal a high diversity of Y-haplogroups. With the exception of Palenque, the sum of European male lineages uniformly exceeded 57%. In Palenque, African lineages accounted for 57.7% of its chromosomes, with European male lineages constituting a mere 38.5%. In Pinillos, a significant proportion (23.8%) of the chromosomes belongs to the Native American haplogroup Q1a3a*-M3. Genetic differentiation analyses reveal significant divergences in most pairwise comparisons among the Bolivar municipalities, and the same holds between Bolivar and other South American populations. CONCLUSIONS: Heterogeneous patterns of admixture reveal a genetic substructure within the Department of Bolivar. On the paternal side, five out of the six communities studied exhibit a predominantly European gene pool. The exception is Palenque, where European input (38%) is more significant than we had expected.


Asunto(s)
Cromosomas Humanos Y/genética , Pool de Genes , Población Negra/genética , Colombia , Humanos , Indígenas Sudamericanos/genética , Masculino , Población Blanca/genética
18.
Sci Rep ; 14(1): 15653, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38977763

RESUMEN

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.


Asunto(s)
Cromosomas Humanos Y , ADN Mitocondrial , Flujo Génico , Variación Genética , Femenino , Humanos , Masculino , África Occidental , Población Negra/genética , Cromosomas Humanos Y/genética , ADN Mitocondrial/genética , Genética de Población , Haplotipos , Herencia Paterna , Pueblo Africano/genética
19.
Forensic Sci Int Genet ; 69: 102999, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38181588

RESUMEN

The Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) organized a collaborative study on mutations of Y-chromosomal short tandem repeats (Y-STRs). New data from 2225 father-son duos and data from 44 previously published reports, corresponding to 25,729 duos, were collected and analyzed. Marker-specific mutation rates were estimated for 33 Y-STRs. Although highly dependent on the analyzed marker, mutations compatible with the gain or loss of a single repeat were 23.2 times more likely than those involving a greater number of repeats. Longer alleles (relatively to the modal one) showed to be nearly twice more mutable than the shorter ones. Within the subset of longer alleles, the loss of repeats showed to be nearly twice more likely than the gain. Conversely, shorter alleles showed a symmetrical trend, with repeat gains being twofold more frequent than reductions. A positive correlation between the paternal age and the mutation rate was observed, strengthening previous findings. The results of a machine learning approach, via logistic regression analyses, allowed the establishment of algebraic formulas for estimating the probability of mutation depending on paternal age and allele length for DYS389I, DYS393 and DYS627. Algebraic formulas could also be established considering only the allele length as predictor for DYS19, DYS389I, DYS389II-I, DYS390, DYS391, DYS393, DYS437, DYS439, DYS449, DYS456, DYS458, DYS460, DYS481, DYS518, DYS533, DYS576, DYS626 and DYS627 loci. For the remaining Y-STRs, a lack of statistical significance was observed, probably as a consequence of the small effective size of the subsets available, a common difficulty in the modeling of rare events as is the case of mutations. The amount of data used in the different analyses varied widely, depending on how the data were reported in the publications analyzed. This shows a regrettable waste of produced data, due to inadequate communication of the results, supporting an urgent need of publication guidelines for mutation studies.


Asunto(s)
Cromosomas Humanos Y , Dermatoglifia del ADN , Humanos , Repeticiones de Microsatélite , Etnicidad/genética , Mutación , Haplotipos , Genética de Población
20.
Ann Hum Biol ; 40(1): 94-8, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23151124

RESUMEN

The Brazilian population is highly heterogeneous as a result of five centuries of inter-ethnic mating between native Amerindians, European colonizers and Africans arrived during slavery. This study aimed to assess the proportions of inter-ethnic admixture in the Brazilian population of Rio de Janeiro using autosomal Ancestry-Informative Markers (AIMs). The autosomal data were also compared to the results expected from uniparental genetic markers. A total of 413 individuals were genotyped for 46 AIM-Indels and ancestry estimates were then assessed using HGDP-CEPH samples as ancestral reference. Individuals from Rio de Janeiro presented highly diverse admixture patterns. The global admixture estimates showed a predominantly European ancestry, above 55%, followed by African and Amerindian contributions. A separate self-declared Afro-descendant group also included in this study revealed an increased African ancestry, from ∼30% to ∼50%. The inter-ethnic admixture landscape of Rio de Janeiro captured by autosomal AIM-Indels is in agreement with historical records and similar to that expected from uniparental mtDNA and Y-chromosome information. The AIM-Indel panel proved to be a rapid strategy to estimate autosomal genetic ancestry at individual and population levels in Rio de Janeiro, which is useful in population genetics and in case-control association studies.


Asunto(s)
Etnicidad/genética , Mutación INDEL , Grupos Raciales/genética , Población Negra , Brasil , Cromosomas Humanos Y/genética , ADN Mitocondrial/genética , Femenino , Frecuencia de los Genes , Marcadores Genéticos , Variación Genética , Genotipo , Humanos , Indígenas Sudamericanos , Masculino , Población Blanca
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