Forensic application of Y-chromosomal STR analysis in Lithuanian population

Abstract

This paper presents a comprehensive Y-chromosomal STR haplotype analysis in the Lithuanian population in order to evaluate Lithuanians’ Y chromosome diversity, to infer genetic relations between Lithuanian and other European neighbouring populations and to introduce population reference data for generation of reliable Y-STR haplotype frequency estimates to be used in the quantitative assessment of Y-STR haplotype match in the forensic casework. Data were collected from the peripheral blood samples of 194 unrelated males throughout various regions of Lithuania. The amplification of 17 Y-STRs was carried out in one multiplex PCR using an AmpFlSTR® Yfiler<sup>TM</sup> PCR Amplication Kit according to the supplier’s protocol. The results indicated that the Y-chromosomal haplotype diversity in the Lithuanian population rises as the number of the analyzed Y-STRs is increased. However, all additional Y-STR loci are not hypervariable and only their whole makes a large diversity of Y-STR haplotypes in Lithuanian males. The analysis of molecular variance revealed low but significant interpopulation differences except the pair of Lithuanian and Latvian populations. The phylogenetic analysis showed that the clustered Y chromosome gene pool of Lithuanians and Latvians has a closer phylogenetic relation to Russian and Estonian populations and is less genetically related to other neighbouring populations of Belarus and Poland. Yet Y-STRs alleles and haplotypes differentiate effectively inside the Lithuanian population and between Lithuanians and its geographical neighbours excluding the Latvian population. Comparison of the Y-STR data suggests that Lithuanian and Latvian populations are closely related not only by geography and language but also by the Y chromosome gene pool represented by forensic Y-STR markers. Consequently, more forensic Y-STR markers should be included in the Y-STR haplotype in order to achieve a resolution between the Y chromosomes of Lithuanian and Latvian males. Lithuanian Y-STR haplotype data were submitted to the 34th release of the Y-STR Haplotype Reference Database 3.0 for match probability calculations in the forensic casework.