Analysis of 10 X-Linked Tetranucleotide Markers in Mixed and Isolated Populations

• NCJ Number: 226989
• Journal: Forensic Science International: Genetics Volume: 3 Issue: 2 Dated: March 2009 Pages: 63-66
• Author(s): Maria T. Zarrabeitia; Fatima Pinheiro; Marian M. de Pancorbo; Laura Caine; Sergio Cardoso; Leonor Gusmao; Jose A Riancho
• Date Published: March 2009
• Length: 4 pages
• Publication Format: Article
• Publication Type: Report (Technical); Report (Study/Research)
• Language: English
• Country: Ireland

Annotation

This study analyzed the population genetic characteristics of the X-linked markers included in the decaplex of four population groups of the Iberian Peninsula, in order to determine the possible differences among mixed and relatively isolated population groups.

Abstract

There were no large differences in allelic frequencies among the population groups studied. Thus, a single reference database can probably be used safely, especially when the case samples are from large mixed populations; however, some evidence was found of population substructure, particularly regarding the Pas Valley. This is a small population with a considerable endogamous tendency. These results confirm previous findings that show markers on the sex chromosomes may reveal between-population differences within the micro geographical range, even though micro satellite allelic frequencies are homogenous across Europe. When forensic cases originate from this sort of population, and a specific reference database is not available, an appropriate correction should be included in the calculations by means of Fst factors; a 5-percent Fst-value is probably a conservative and safe correction for substructure. A total of 525 individuals belonging to 4 population groups were studied. Group 1 included 107 unrelated individuals (55 men and 52 women) living in the coastal area of Cantabria, a region in Northern Spain with a population of 530,000. Group 2 included 86 individuals (50 men and 36 women) of the Pas Valley, which is in the southern part of Cantabria, an isolated mountainous area. Group 3 included 132 individuals (47 men and 85 women) with ancestors from the Basque Country in northern Spain. Group 4 included 100 men and 100 women from the North of Portugal, which includes major cities and rural areas. In addition to the study groups, this report describes STR amplification and typing, as well as data analysis. 1 Figure, 3 tables, appendix, and 24 references