NCJ Number
227238
Journal
Forensic Science International: Genetics Volume: 3 Issue: 3 Dated: June 2009 Pages: 173-178
Date Published
June 2009
Length
6 pages
Annotation
Using a recently developed commercial X-chromosome typing kit (Mentype Argus X-8) to supplement the existing forensic toolkit, this study examined X-STR allele frequencies and population diversity indexes in two ethnic groups, the Finnish and the Somali.
Abstract
Several previously unreported alleles and features in the allelic distribution were observed, some of which were further investigated with a small set of family data. At 6 loci, 36 alleles not falling into the predefined allele bins were found, 32 in the Somali and 9 in the Finnish sample. Out of these, 16 alleles observed in the Somali and 1 in the Finnish sample have not, to the authors’ knowledge, been previously reported. All 8 loci included in the Mentype Argus X-8 kit were found to be polymorphic in both population samples, with the number of alleles varying between 4 (DXS8738 among the Somali) and 34 (DXS10135 among the Somali). The Somali population had slightly more variation. Notably, several alleles showed significant frequency differences between sexes, yet no obvious explanation for this discrepancy was found. In order to demonstrate X-chromosome analysis in practice, this paper describes two family reunion cases in which the X-STR data were successfully used. Currently, the incompletely known diversity spectrum at the X-STR loci suggest caution in the application of the X-chromosome in casework. The need for modifications in order to avoid overlapping DNA-markers is clear, along with an updated allele bin set for the analysis program. Altogether, 700 anonymous Finnish and Somali samples were included in this study. These samples were collected either with informed consent for research purposes or chosen randomly from the casework samples. 2 tables and 15 references