X-chromosome STR markers data in a Cabo Verde immigrant population of Lisboa

Haplotype data and forensic evaluation of 23 Y-STR and 12 X-STR loci in eight ethnic groups from Eritrea

Eritrea is a multi-ethnic country of over 3 million of people consisting of different ethnic groups, having each its own language and cultural tradition. Due to the lack of population genetic data for markers of forensic interest, in this study, we analyzed the genetic polymorphisms of 23 Y-chromosome STR loci and of 12 X-chromosome STR loci in a sample of 255 unrelated individuals from 8 Eritrean ethnic groups, with the aim to generate a reference haplotype database for anthropological and forensic applications. X- and Y-chromosomes markers may indeed offer information especially in personal identification and kinship testing, when relying on the availability of large local population data to derive sufficiently accurate frequency estimates. The population genetic analyses in the Eritrean sample for both the two set of Y- and X-STR markers showed high power of discrimination both at country-based and population levels. Comparison population results highlight the importance of considering the ethnic composition within the analyzed country and the necessity of increasing available data especially when referring to heterogeneous populations such as the African ones.

Expanded Croatian 12 X-STR loci database with an overview of anomalous profiles

In order to implement X-chromosome short tandem repeat (X-STR) typing into routine forensic practice, reference database of a given population should be established. Therefore we extended already published data with additional 397 blood samples from unrelated Croatian citizens, and analyzed the total of 995 samples (549 male and 446 female) typed by Investigator^® Argus X-12 Kit. To test genetic homogeneity of consecutively processed five historic-cultural regions covering the entire national territory, we calculated pairwise Fst genetic distances between regions based on allele and full haplotype frequencies. Since the comparison did not yield any statistically significant difference, we integrated STR profile information from all regions and used the whole data set to calculate forensic parameters. The most informative marker is DXS10135 (polymorphism information content (PIC = 0.929) and the most informative linkage group (LG) is LG1 (PIC = 0.996). We confirmed linkage disequilibrium (LD) for seven marker pairs belonging to LG2, LG3 and LG4. By including LD information, we calculated cumulative power of discrimination that amounted to 0.999999999997 in females and 0.999999005 in males. We also compared Croatia with 13 European populations based on haplotype frequencies and detected no statistically significant Fst values after Bonferroni correction in any LG. Multi-dimensional scaling plot revealed tight grouping of four Croatian regions amongst populations of southern, central and northern Europe, with the exception of northern Croatia. In this study we gave the first extensive overview of aberrant profiles encountered during Investigator^® Argus X-12 typing. We found ten profiles consistent with single locus duplication followed by tetranucleotide tract length polymorphism. Locus DXS10079 is by far the most frequently affected one, presumably mutated in eight samples. We also found four profiles consistent with X-chromosome aneuploidy (three profiles with XXX pattern and one profile with XXY pattern). In conclusion, we established integral forensic Croatian X-chromosome database, proved forensic pertinence of Investigator^® Argus X-12 Kit for the entire Croatian population and identified locus DXS10079 as a potential duplication hotspot.

Analysis of 12 X-STR loci in the population of south Croatia

The aim of the study was to assess forensic pertinence of 12 short tandem repeats (STRs) on X-chromosome in south Croatia population. Investigator^® Argus X-12 kit was used to co-amplify 12 STR loci belonging to four linkage groups (LGs) on X-chromosome in 99 male and 98 female DNA samples of unrelated donors. PCR products were analyzed by capillary electrophoresis. Population genetic and forensic parameters were calculated by the Arlequin and POPTREE2 software, and an on-line tool available at ChrX-STR.org. Hardy-Weinberg equilibrium was confirmed for all X-STR markers in female samples. Biallelic patterns at DXS10079 locus were detected in four male samples. Polymorphism information content for the most (DXS10135) and the least (DXS8378) informative markers was 0.9212 and 0.6347, respectively. In both male and female samples, combined power of discrimination exceeded 0.999999999. As confirmed by linkage disequilibrium test, significant association of marker pair DXS10074-DXS10079 (P = 0.0004) within LG2 and marker pair DXS10101-DXS10103 (P = 0.0003) within LG3 was found only in male samples. Number of observed haplotypes in our sample pool amounted 3.01, 7.53, 5 and 3.25% of the number of possible haplotypes for LG1, LG2, LG3 and LG4, respectively. According to haplotype diversity value of 0.9981, LG1 was the most informative. In comparison of south Croatia with 26 world populations, pair-wise [Formula: see text] values increase in parallel with geographical distance. Overall statistical assessment confirmed suitability of Investigator^® Argus X-12 kit for forensic casework in both identification and familial testing in the population of south Croatia.

Study of InDel genetic markers with forensic and ancestry informative interest in PALOP's immigrant populations in Lisboa

The migratory phenomenon in Portugal has become one of the main factors for the genetic variability. In the last few years, a new class of autosomal insertion/deletion markers-InDel-has attracted interest in forensic genetics. Since there is no data for InDel markers of Portuguese-speaking African countries (PALOP) immigrants living in Lisboa, our aim is the characterization of those groups of individuals by typing them with at least 30 InDel markers and to compare different groups of individuals/populations. We studied 454 bloodstain samples belonging to immigrant individuals from Angola, Guinea-Bissau, and Mozambique. DNA extraction was performed with the Chelex® 100 method. After extraction, all samples were typed with the Investigator® DIPplex method. Through the obtained results, allelic frequencies show that all markers are at Hardy-Weinberg equilibrium, and we can confirm that those populations show significant genetic distances between themselves, between them, and the host Lisboa population. Because of this, they introduce genetic variability in Lisboa population.