Short tandem repeats (STRs) of the combined DNA index system (CODIS) are probably the most employed markers for human identification purposes. STR databases generated to interpret DNA profiles are also helpful for anthropological purposes. In this work,

Different dynamics of gene flow and drift were observed among Mexican Native groups, highlighting the geographic barriers (mountains, canyons and jungle regions) as the main factor differentiating Pre-Hispanic populations, and eventually helping to avoid Post-European contact admixture and population bottleneck. Am J Phys Anthropol 160:298-316, 2016. © 2016 Wiley Periodicals, Inc.

We previously documented the lowest frequency of CYP2C9*2 in Mexican indigenous Tepehuanos followed by Mestizos and Mexican-Americans populations, suggesting a negative correlation between the CYP2C9*2 frequency and the degree of Asian ancestry in indigenous Americans. We determined the influence of ethnic admixture components on the CYP2C9 allele distribution in 505 Amerindian from eight indigenous populations through genotyping CYP2C9*2, *3 and *6 alleles by real-time PCR and molecular evaluation of ancestry. The frequencies for CYP2C9*2 were 0.026 in Seris and 0.057 in Mayos, being higher than in Asians (P<0.001). CYP2C9*3 was found in Tarahumaras (0.104), Mayos (0.091), Tepehuanos (0.075), Guarijíos (0.067), Huicholes (0.033) and Coras (0.037), with East Asians having lower frequencies than the former three groups (P<0.001). CYP2C9*6 was not found. The frequency of CYP2C9*2 was lower in Amerindians than in European populations, and higher than their Asian ancestors. The presence of this allele in ethnic groups in Mexico can be explained by European admixture.

CYP2C19 is a polymorphic enzyme that metabolizes a wide variety of therapeutic drugs that has been associated with altered enzymatic activity and adverse drug reactions. Differences in allele frequencies of the CYP2C19 gene have been detected in populations worldwide. Thus, we analysed the alleles CYP2C19*2, CYP2C19*3, CYP2C19*4 and CYP2C19*5 related to the poor metabolizer (PM) phenotype in a Mexican population sample (n = 238), as well as CYP2C19*17, unique allele related to ultrarapid metabolizer phenotype (UMs). Genotypes were determined using SNaPshot and TaqManqPCR assays. In addition to the wild-type CYP2C19*1 allele (77.1%), we only found CYP2C19*17 (14.3%) and CYP2C19*2 (8.6%). Comparison with previous population reports demonstrated that these two SNPs are homogeneously distributed in Latin America (P > 0.05). Based on comparison with a previous pharmacokinetic study that determined the frequency of CYP2C19 phenotypes in the same population (western Mexican), we obtained the following findings: (i) based on the difference between the frequency of genotypes CYP2C19*2/*2 (presumably PM) versus the observed prevalence of PM phenotypes (0.4 versus 6.3%; Χ(2) = 9.58, P = 0.00196), we inferred the plausible presence of novel CYP2C19 alleles related to the PM phenotype; (ii) the prevalence of UMs was in disagreement with the dominant inheritance pattern suggested for CYP2C19*17 (23.1 versus 4%; P < 0.00001); (iii) the apparent recessive inheritance pattern of CYP2C19*17, based on the agreement between homozygous CYP2C19*17/*17 (presumably UMs) and the observed prevalence of UMs (2.1 versus 4%; (Χ(2) = 1.048; P = 0.306).