Genetic polymorphism and forensic parameters of nine short tandem repeat loci in Ngobe and Embera Amerindians of Panama

Abstract

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 Ngöbé 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 the use of additional loci supplementing the battery of the nine loci is recommended for paternity and forensic tests in both populations, particularly for the Ngöbé.