Genetic polymorphism and forensic parameters of nine short tandem repeat loci in Ngöbé and Emberá Amerindians of Panama.

Nine STR loci (CSF1PO, TPOX, TH01, F13A01, FESFPS, VWA, D16S539, D7S820, and D13S317) were analyzed in unrelated Ngöbé and Emberá Amerindians of Panama. The chi-square test demonstrated statistically significant differences (P < 0.001) in the allele frequencies for all markers except one (D16S539; P < 0.01). Both populations shared their alleles with the highest frequencies in seven loci. However, there were also noticeable differences at the TPOX locus, which showed its highest frequencies at alleles 11 (0.48) and 6 (0.54) for the Ngöé and Emberá, respectively. Interestingly, these alleles are present in one population and are absent in the other, suggesting that they could be distinctive for each population. These results demonstrate that, despite the fact that each population belongs to a different linguistic stock [Chibchan (Ngöbé) and Chocoan (Emberá)], both retain strong similarities in their allele-frequency distributions. Three loci (TPOX, VWA, and F13A01) in the Ngöbé and two loci (TH01 and TPOX) in the Emberá departed from Hardy-Weinberg equilibrium. The analysis of the STR markers demonstrates that, despite their low levels of genetic polymorphisms, most of them could be informative for forensic purposes, showing a combined power of discrimination of 0.9999 for both Amerindian populations. However, powers of exclusion in the Ngöbé were very low, particularly at the TH01 (0.04) and FESFPS (0.08) loci. The combined powers of exclusion were 0.9338 and 0.9890 for the Ngöbé and the Emberá, respectively. Furthermore, the combined typical paternity index in the Ngöbé was considerably low (2.58), and in the Emberá it was 40.44, which is also very low. The low genetic polymorphism levels suggest that theuse of additional loci supplementing the battery of the nine loci is recommended for paternity and forensic tests in both populations, particularly for the Ngöbé.

Analysis of six SNPs of NAT2 in Ngawbe and Embera Amerindians of Panama and determination of the Embera acetylation phenotype using caffeine.

Six NAT2 single-nucleotide polymorphisms (SNPs) were analysed in 105 unrelated Ngawbe and 136 unrelated Embera Amerindians (482 chromosomes) by SNP-specific polymerase chain reaction analysis. 282C>T was the most common synonymous mutation, while 857G>A was the most frequent nonsynonymous inactivating exchange. The allelic frequency of the NAT2*5 series (containing the 341T>C exchange) was 2.4% and 9.9% for Ngawbe and Embera, respectively, five- to 20-times lower than that in Caucasians. The NAT2*6 series (590G>A) showed allelic frequencies of 0% and 3.7%, eight- to 30-times lower than in Caucasians. On the other hand, the NAT2*7 series, characterized by mutation 857G>A, had allelic frequencies (23.3% and 22.8%) that were 10-20-times higher in Amerindians than in Caucasians. Amerindians are characterized by decreased genetic diversity because they display a low number of mutated alleles (four and five for Ngawbe and Embera, respectively) that are present at low proportions (27.6% and 39%), reduced genotypic variability (seven out of 15 and 12 out of 21 possible genotypes) and low heterozygosity (40% and 55.1%) at the NAT2 locus. The NAT2 phenotype was evaluated with caffeine in a subset of 72 Embera. There were no disagreements between genotype and phenotype among rapid and slow acetylators (13/72, 18%). We conclude that, in the Embera, the analysis of three inactivating mutations was sufficient in predicting the phenotype in more than 99.5% of these subjects. NAT2 would appear to be of a selectively neutral character given that there is no evidence of adaptation to the prevailing ecology in Amerindians.

[Racial mix of the panamanian population]. / La mezcla racial de la población panameña.

The racial admixture of a target population can be ascertained by quantifying the contribution to the genetic pool of each of its components (ancestral populations), which could be two, three or more. The racial admixture is of importance for the understanding of results derived from biomedical and anthropological studies. The main objective of this investigation is to determine the population frequencies of genetic systems ABO and Rh and to use these data to calculate the racial admixture of the country and of each sample province, fitting a trihybrid model. To achieve this, the Krieger method, implemented by the computer program Mistura 3, was applied to phenotypic data of systems ABO and Rh in a sample of 4,202 subjects born in seven provinces. In the general population of Panama, 38.72% of genes from the genetic pool have an African origin, 35.87%, an Amerindian origin and 25.40%, a Caucasian origin. In the province of Cocle we found a contribution of 16.47% of African genes, 55.25% of Amerindian genes and 28.28% of Caucasian genes. The province of Colon presents 69.34% of African genes, 25.00% of Amerindian genes and 5.65% of Caucasian genes. In contrast, Chiriquí presents 5.56% of African genes, 50.63% of Amerindian genes and 43.80% of Caucasian genes. The province of Herrera is characterized by the following proportions: 58.45% African genes, 28.44% Amerindian genes and 13.11% Caucasian genes. In the province of Los Santos there is a 62.29% African contribution, a 14.35% Amerindian contribution and a 22.72% Caucasian one. In the province of Panama there is a 57.01%, 26.25% and 16.74% contribution of African, Amerindian and Caucasian genes, respectively. Finally, in Veraguas a contribution of 18.59% of African genes, 44.29% of Amerindian genes and 37.12% of Caucasian genes was found.

Estudio preliminar sobre el fenotipo de acetilador de los amerindios Teribes / Preliminar study on the phenotype of acetylator of Teribe Amerindians

El estudio de la capacidad de acetilación en 62 voluntarios teribes, procedentes de Sieykin, Sieyic y Santa Rosa, demonstró que 48.4% eran acetiladores rápidos y 51.6%, acetiladores lentos. Al comprobar estos resultados con los que obtuvimos en una población cuna, en la cual encontramos que el 78% era de acetiladores rápidos, se observa que tanto la distribución de los sujetos estudiados, según el porcentaje de isoniacida que acetilaron, como el porcentaje de acetiladores lentos y rápidos indican que, en ambos grupos, existen diferencias en la actividad de la N-acetiltransferasa. Estos resultados sugieren que pueden existir diferencias fundamentales entre los diferentes grupos amerindios, en la habilidade de biotransformar los medicamentos

La biotransformación de la esparteína en amerindios cunas de Panamá / Biotransformation of sparteine in Amerindians cunas of Panamá

Reportamos, por vez primera, un estudio de oxidación metabólica en un grupo amerindio: los cunas de Panamá. Estudios genéticos indican un escaso mestizaje de menos del 1% de mezcla racial y establecen la identidad genética del grupo cuna con respecto a otros grupos amerindios que se remonta, a lo menos, a 5,000 años. Ciento nueve voluntarios recibieron 50 mg de esparteína y recogieron sus orinas por 12 horas, para determinar la cantidad que contenían de esparteína y de sus dos productos de oxidación. El porcentaje del medicamento intacto recuperado de la orina, así como de sus metabolitos, fue menor que el encontrado en otros grupos étnicos y está normalmente distribuido. La razón metabólica, que es un índice de eficiencia de la actividad de la isozima involucrada en la biotransformación de la esparteína, indica que no existen metabolizadores deficientes en este grupo y que la frecuencia de los metabolizadores extensos muestra una distribución unimodal. Por esas razones concluimos diciendo que en el grupo cuna, a diferencia de los grupos caucasoides, no existe polimorfismo en la oxidación de la esparteína. Además la ausencia de metabolizadores deficientes entre los cunas indica que este grupo, en comparación con los caucasoides, se encuentra en menor riesgo de desarollar reacciones tóxicas al usar medicamentos que siguen la ruta de la esparteína