Interpretation Guidelines of a Standard Y-chromosome STR 17-plex PCR-CE Assay for Crime Casework
Y-STR analysis is an invaluable tool to examine evidence in sexual assault cases and in other forensic casework. Unambiguous detection of the male component in DNA mixtures with a high female background is still the main field of application of forensic Y-STR haplotyping. In the last years, powerful technologies including a 17-locus multiplex PCR assay have been introduced in the forensic laboratories. At the same time, statistical methods have been developed and adapted for interpretation of a nonrecombining, linear marker as the Y-chromosome which shows a strongly clustered geographical distribution due to the linear inheritance and the patrilocality of ancestral groups. Large population databases, namely the Y-STR Haplotype Reference Database (YHRD), have been established to assess the evidentiary value of Y-STR matches by means of frequency estimation methods (counting and extrapolation).
Key wordsY-STR analysis Sexual assault Mixed stains Haplotype frequency Match probability Mixture analysis Population database
The author wishes to thank all colleagues of the Forensic Y-Chromosome User Group for their engaged work on the YHRD database project (www.yhrd.org/Search/Contributors). Sascha Willuweit (YHRD curator, Institute of Legal Medicine and Forensic Sciences Berlin, Germany) is greatly acknowledged for his contribution to this manuscript.
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