Heterogeneous mt-DNA Haplogroup Distribution in Immigration Countries - Call for Local Database Feasibilities for Forensic Purposes: The EMPOP Efforts

ANDREA SALA, MIGUEL MARINO, ANITA BRANDSTATTER, CECILIA BOBILLO, WALTHER PARSON AND DANIEL CORACH..

Insbruck

Congreso; 5th International Y-User Workshop "The Y chromosome in forensic, clinical and evolutionary genetics"; 2006

The American continent is a good example of immigration territory. It received three major ethnic contributions. The first immigrants came from Asia, determining the peopling of the continent; this process took place between 18-20 Ky ago. The immigrants widespread from Alaska to Tierra del Fuego along 8-10 ky ago. During this period peculiar traits were developed and some of them fixed in the immigrant population. The second major immigrant wave come from Europe and was produced only 0.5ky ago and its effects were dramatic on the aboriginal Asia-rooted “natives”. Although, a massive reduction of the aboriginal population was produced a big deal of admixture took place. Accordingly, an important genetic contribution provided by the aboriginal remained. The third component was brought as working force from Africa during XVII through XIX centuries. Directional mating determined that aboriginal female genetic contribution widespread and admixed with European male immigrants. Accordingly, the resulting extant populations are far from being genetically homogeneous, although some countries like Argentina and Uruguay to be of almost “pure” European ancestry claimed it. By typing Amerindian-specific Y chromosome haplogroups it became apparent that about 20% of the population have aboriginal patrilineage ancestry. In contrast, when analyzing mtDNA D-Loop sequences it was demonstrated that over 60% of the randomly sampled individuals depicted Amerindian-specific haplogroups (A, B, C and D). Meanwhile, less than 40% denoted non-Amerindian mtDNA hgs, within this subset, the most frequent hg was H (12,9 %), U (6.3%), T (2.8%) and only 1.4% exhibited L hg of possible African ancestry. The overall heterogeneous Hgs distribution represent a serious challenge for estimating mtDNA haplotype frequencies required for forensic purposes. The pretended use of foreign mtDNA references database may lead to serious frequency estimation bias and determine erroneous conclusions. The continuous efforts made by the European Mitochondrial Population (EMPOP) Database to improve and optimize the quality of the accepted sequences might warrant a reliable tool for frequency estimation and haplogroup determination. Due to the restriction imposed by the heterogeneity of the haplogroup frequency distribution and hence the overall haplotype diversity in the different world regions, the opportunity to create local reference databases hosted in a worldwide major reference facility as EMPOP, will strongly contribute with the forensic scientist all over the world.