Genetic analysis of 17 Y-STRs in a Mestizo population from the Central Valley of Mexico

This study aims to portray the complex diversity of the Mexican Mestizo population, which represents 98.8% of the entire population of Mexico. We compiled extended haplotype data of the Y chromosome from populations in the Central Valley of Mexico (CVM), which were compared to other Mestizo and parental (Amerindian, European and African) populations. A complex ancestral relationship was found in the CVM population, suggesting cosmopolitan origins. Nevertheless, the most preeminent lineages point towards a European ancestry, where the R1b was the most frequent. In addition, important frequencies of Amerindian linages were also found in the Mestizo sample studied. Interestingly, the Amerindian ancestry showed a remarkable substructure, which was represented by the two main founding lineages: QL54 (x M3) and M3. However, even within each lineage a high diversity was found despite the small number of samples bearers of these lineages. Further, we detected important genetic differences between the CVM populations and the Mexican Mestizo populations from the north and south. This result points to the fact that Mestizo populations present different ancestral proportions, which are related to the demographic events that gave origin to each population. Finally, we provide additional forensic statistical parameters that are useful in the interpretation of genetic analysis where autosomal loci are limited. Our findings illustrate the complex genetic background of the Mexican Mestizo population and reinforce the need to encompass more geographic regions to generate more robust data for forensic applications

Association of vWA and TPOX Polymorphisms with Venous Thrombosis in Mexican Mestizos

Objective. Venous thromboembolism (VTE) is a multifactorial disorder and, worldwide, the most important cause of morbidity and mortality. Genetic factors play a critical role in its aetiology. Microsatellites are the most important source of human genetic variation having more phenotypic effect than many single nucleotide polymorphisms. Hence, we evaluate a possible relationship between VTE and the genetic variants in von Willebrand factor, human alpha fibrinogen, and human thyroid peroxidase microsatellites to identify possible diagnostic markers. Methods. Genotypes were obtained from 177 patients with VTE and 531 nonrelated individuals using validated genotyping methods. The allelic frequencies were compared; Bayesian methods were used to correct population stratification to avoid spurious associations. Results. The vWA-18, TPOX-9, and TPOX-12 alleles were significantly associated with VTE. Moreover, subjects bearing the combination vWA-18/TPOX-12 loci exhibited doubled risk for VTE (95% CI = 1.02-3.64), whereas the combination vWA-18/TPOX-9 showed an OR = 10 (95% CI = 4.93-21.49). Conclusions. The vWA and TPOX microsatellites are good candidate biomarkers in venous thromboembolism diseases and could help to elucidate their origins. Additionally, these polymorphisms could become useful markers for genetic studies of VTE in the Mexican population; however, further studies should be done owing that this data only show preliminary evidence

Forensic-paternity effectiveness and genetics population analysis of six non-CODIS mini-STR loci (D1S1656, D2S441, D6S1043, D10S1248, D12S391, D22S1045) and SE33 in Mestizo and Amerindian populations from Mexico

<p><b>Background:</b> STRs are powerful tools intensively used in forensic and kinship studies.</p> <p><b>Aim:</b> In order to assess the effectiveness of non-CODIS genetic markers in forensic and paternity tests, the genetic composition of six mini short tandem repeats<i>—</i>mini-STRs<i>—</i>(D1S1656, D2S441, D6S1043, D10S1248, D12S391, D22S1045) and the microsatellite SE33 in Mestizo and Amerindian populations from Mexico were studied.</p> <p><b>Subjects and methods:</b> Using multiplex polymerase chain reactions and capillary electrophoresis, this study genotyped all loci from 870 chromosomes and evaluated the statistical genetic parameters.</p> <p><b>Results:</b> All mini-STRs studied were in agreement with HW and linkage equilibrium<i>;</i> however, an important HW departure for SE33 was found in the Mestizo population (<i>p</i> <i>≤</i> 0.0001). Regarding paternity and forensic statistical parameters, high values of combined power discrimination and mean power of exclusion were found using these seven markers. The principal co<i>-</i>ordinate analysis based on allele frequencies of three mini-STRs showed the complex genetic architecture of the Mestizo population.</p> <p><b>Conclusion:</b> The results indicate that this set of loci is suitable to genetically identify individuals in the Mexican population, supporting its effectiveness in human identification casework. In addition, these findings add new statistical values and emphasi<i>s</i>e the importance of the use of non-CODIS markers in complex populations in order to avoid erroneous assumptions.</p