Comparative Study of 10 X-STR Markers in Populations of Northeast Argentina.

In northeast Argentina, different Amerindian communities share territory and history with settlers, mainly Europeans. Due to miscegenation, the current Argentinean population has a particular structure that can be described through X chromosome variation. The objectives of this study were to describe the variation of 10 X-chromosome short tandem repeats (X-STRs) in urban populations of the Argentinean regions known as Gran Chaco and Mesopotamia, report the forensic parameters of these STRs, and estimate the European and indigenous genetic components in these regions. Population and forensic parameters were estimated for 419 individuals from the analyzed populations, including two indigenous groups, Wichí and Mocoví, previously reported. Population structure was estimated through FST and RST distances and analysis of molecular variance. The indigenous American and European components were assessed with STRUCTURE. X-STRs showed a high level of genetic variability in urban and indigenous populations. Indigenous people of the Gran Chaco region showed significant differentiation from the urban samples (FST = 5.5%) and among themselves (FST = 5.3%). Genetic differentiation among urban groups was almost negligible, except that the population from Misión Nueva Pompeya differed from the rest of the city populations. Forensic parameters indicate that these X-STRs are useful as a complement to paternity tests. The set of 10 STRs could be a good tool for examining population differences.

Genetic Differentiation of North-East Argentina Populations Based on 30 Binary X Chromosome Markers.

Alu insertions, INDELs, and SNPs in the X chromosome can be useful not only for revealing relationships among populations but also for identification purposes. We present data of 10 Alu insertions, 5 INDELs, and 15 SNPs of X-chromosome from three Argentinian north-east cities in order to gain insight into the genetic diversity of the X chromosome within this region of the country. Data from 198 unrelated individuals belonging to Posadas, Corrientes, and Eldorado cities were genotyped for Ya5DP62, Yb8DP49, Ya5DP3, Ya5NBC37, Ya5DP77, Ya5NBC491, Ya5DP4, Ya5DP13, Yb8NBC634, and Yb8NBC102 Alu insertions, for MID193, MID1705, MID3754, MID3756 and MID1540 Indels and for rs6639398, rs5986751, rs5964206, rs9781645, rs2209420, rs1299087, rs318173, rs933315, rs1991961, rs4825889, rs1781116, rs1937193, rs1781104, rs149910, and rs652 SNPs. No deviations from Hardy-Weinberg equilibrium were observed for Posadas and Corrientes. However, Eldorado showed significant values, and it was found to have an internal substructuring with two groups of different origin, one showing higher similarity with European countries, and the other with more similarities to Posadas and Corrientes. Fst pairwise genetic distances emerged for some markers among the studied populations and also between our data and those from other countries and continents. Of particular interest, Alu insertions demonstrated the most differences, and could be of use in ancestry studies for these populations, while INDELs and SNPs variation were informative for differentiation within the country.

Forensic analysis of dog (Canis lupus familiaris) mitochondrial DNA sequences: an inter-laboratory study of the GEP-ISFG working group.

A voluntary collaborative exercise aiming at the mitochondrial analysis of canine biological samples was carried out in 2006-2008 by the Non-Human Forensic Genetics Commission of the Spanish and Portuguese Working Group (GEP) of the International Society for Forensic Genetics (ISFG). The participating laboratories were asked to sequence two dog samples (one bloodstain and one hair sample) for the mitochondrial D-loop region comprised between positions 15,372 and 16,083 using suggested primers and PCR conditions, and to compare their results against a reference sequence. Twenty-one participating laboratories reported a total of 67.5% concordant results, 15% non-concordant results, and 17.5% no results. The hair sample analysis presented more difficulty to the participants than the bloodstain analysis, with a high percentage (29%) failing to obtain a result. The high level of participation showed the interest of the community in the analysis of dog forensic samples but the results reveal that crucial methodological issues need to be addressed and further training is required in order to respond proficiently to the demands of forensic casework.

Geographic structure in Gran Chaco Amerindians based on five X-chromosome STRs.

We investigated the genetic differentiation of five X-chromosome STR markers among five native South American Amerindian populations inhabiting three different areas of the Gran Chaco: Mocoví, Chorote, Wichí, Lengua, and Ayoreo. The observed genetic structure showed correspondence with geographic distribution more clearly than previous information obtained from autosomal STRs for the same samples. On the other hand, X-chromosome STR data did not agree with linguistic affinities. These markers proved to be informative for the study of the native populations of the Gran Chaco region.

Autosomal rearrangements in Graomys griseoflavus (Rodentia): a model of non-random Robertsonian divergence.

The south American rodent Graomys griseoflavus exhibits a remarkable chromosome polymorphism as a consequence of four Robertsonian fusions. Focusing on the genetic analysis of the taxon, genome organization of all karyomorphs was studied at chromosome and molecular organization level. Cytogenetic (G, NOR and Re banding) and molecular (satellite and mitochondrial DNAs) events accompanying chromosome divergence allowed tracing a phylogenetic relationship among all karyomorphs. Available data led to propose that chromosome evolution of G. griseoflavus occurred in a non-random sequence of centric fusions, supporting the hypothesis of single origin for Robertsonian karyomorphs.