Population data of F13AO1, FES/FPS, VWA, CSF1PO, TPOX and THO1 short tandem repeat loci in a sample of African descent individuals of Colombia

Signs of continental ancestry in urban populations of Peru through autosomal STR loci and mitochondrial DNA typing

The human genetic diversity around the world was studied through several high variable genetic markers. In South America the demic consequences of admixture events between Native people, European colonists and African slaves have been displayed by uniparental markers variability. The mitochondrial DNA (mtDNA) has been the most widely used genetic marker for studying American mixed populations, although nuclear markers, such as microsatellite loci (STRs) commonly used in forensic science, showed to be genetically and geographically structured. In this work, we analyzed DNA from buccal swab samples of 296 individuals across Peru: 156 Native Amazons (Ashaninka, Cashibo and Shipibo from Ucayali, Huambiza from Loreto and Moche from Lambayeque) and 140 urban Peruvians from Lima and other 33 urban areas. The aim was to evaluate, through STRs and mtDNA variability, recent migrations in urban Peruvian populations and to gain more information about their continental ancestry. STR data highlighted that most individuals (67%) of the urban Peruvian sample have a strong similarity to the Amazon Native population, whereas 22% have similarity to African populations and only ~1% to European populations. Also the maternally-transmitted mtDNA confirmed the strong Native contribution (~90% of Native American haplogroups) and the lower frequencies of African (~6%) and European (~3%) haplogroups. This study provides a detailed description of the urban Peruvian genetic structure and proposes forensic STRs as a useful tool for studying recent migrations, especially when coupled with mtDNA.

Population data on 15 autosomal STRs in a sample from Colombia

We present population genetic data of 15 STRs (CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, PENTA D, PENTA E, TH01, TPOX and VWA) obtained from a sample of 617 unrelated individuals from Colombia. Deviations from Hardy-Weinberg equilibrium were assessed and allele frequencies and parameters of forensic interest for each STR were calculated. The combined power of exclusion (PE) and the combined power of discrimination (PD) for the 15 tested STR loci were 0, 99999895 and more than 0, 9999999, respectively. The combined MP value was 1 in 1, 07888 x 10(-17). Population comparisons between our sample and neighbouring populations from Latin America were carried out. Significant differences in above six markers were observed between our sample and two populations from Rio de Janeiro.

Admixture estimates for Churuguara, a Venezuelan town in the State of Falcón

BACKGROUND

The present Venezuelan population is the admixture product of Amerindians, Europeans and Africans, a process which was not homogeneous over the country. Blood groups, STRs and VNTRs, specifically D1S80, have been used successfully in admixture studies, but few have been made in Venezuela.

AIM

This study aims to estimate the admixture components of Churuguara, Venezuela, and to evaluate the genetic relationship of this population with other Venezuelan as well as worldwide populations through principal component analysis and the study of dendrograms based on genetic distances.

SUBJECTS AND METHODS

Gene frequencies of blood groups ABO and Rh (only anti D), of STRs VWA, F13A01, FES/FPS and VNTR D1S80 were studied in a sample of 60 individuals born in Churuguara, a Venezuelan town of admixed ancestry in the State of Falc6n. Admixture was estimated with Chakraborty's gene identity method, and Nei's standard genetic distance was used to build two dendrograms with the neighbour-joining approach, one based on the three STRs and the other based only on D1S80. Principal component analyses with the gene frequencies of these markers were also performed.

RESULTS

The frequency of allele ABO*O was 0.788, of ABO*A was 0.187 and of RH*D was 0.74. D1S80 showed 16 different alleles with a heterozygosity of 0.880, whilst the three STRs showed only eight different alleles and heterozygosities between 0.733 and 0.797. The estimates of admixture obtained in this analysis were 52.5% for the Spanish parental group, 27.6% for the African and 19.9% for the Amerindian. Comparison of Churuguara with other Latin American populations shows that its African component is not as high as that observed in Colombian Choco, but it is higher than that observed in other samples from Colombia, Chile and Maracaibo (Venezuela).

CONCLUSIONS

Results of the admixture analysis are consistent with those obtained with two dendrograms and principal component analyses, suggesting that the strong initial Amerindian component of 500 years ago has been diluted by the continuous flow of European genes, mainly Spanish, to this region.

Analysis of the CODIS autosomal STR loci in four main Colombian regions

Genotype polymorphism studies at the 13 loci STRs included in the combined DNA index system [CODIS and PCR-based short tandem repeat loci, in: Proceedings of the Second European Symposium on Human Identification, Promega Corporation, Madison, WI, 1998, pp. 73-88; J. Forensic Sci. 46 (2001) 453] (CODIS: D3S1358, HUMvWA31, HUMFGA, D8S1179 D21S11, D18S51, D5S818, D13S317, D7S820, HUMTH01, HUMTPOX, HUMCSF1PO and D16S539) were carried out in a sample of 1429 unrelated Colombian individuals belonging to 25 different departments. As many other countries in Latino-America, Colombia shows an important admixture component, basically integrated by Amerindians, European-descendants and African-descendants. Due to the fact that only partial population analyses have been carried out in the country, the main aim of the present analysis is to establish a database of forensic interest based on the widely used CODIS systems covering the main Colombian regions.

Allelic frequencies at 12 STR loci in Colombian population

Three hundred and twenty-six to four hundred and fifty-one individuals were typed for 12 STR markers and revealed by silver stain method and assisted by a computer analysis. Forensic and Hardy-Weinberg values were found. The Kodak ds 1D Image Analysis Software V 2.0.3 EDAS DC 120 System was a useful tool for determining the correct size of pattern bands that were out allelic ladders, alleles 18 and 17 from F13A01, 15 from TPOX and 4 from TH01 were determined by this method and some corroborated by automatic analysis.