A new duplex PCR system for YCAII and DXYS156Y microsatellites analysis

Abstract

The Y-chromosome polymorphisms represent an important tool in forensic genetics for different purposes: paternity testing, special problems of medical genetics, such as incest causing autosomal recessive diseases, analysis of mixed stains and other biological samples in criminal events. The number of Y-chromosome polymorphisms is huge, but only a well-defined number of them are used in official protocols of the international forensic genetics community. Recently, we presented a definitive haplotype of Y-STR in 107 unrelated individuals living in a Tuscany population (Central Italy) [Forensic Sci. Int. 120 (2001) 210]. To study this “minimal haplotype” we used the markers DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS385I/II [Forensic Sci. Int. 114 (2000) 31]. Subsequently, we introduced in our laboratory the use of an automated infrared DNA sequencer (LI-COR 4200). We applied this technology to study the hypervariable locus YCAII [Hum. Mol. Genet. 3 (1994) 115] for the “extended haplotype” and the polymorphism DXYS156 [Int. J. Legal Med. 110 (1997) 125], suggested by Kayser et al. [Hum. Biol. 70 (1998) 979]. We set up a new duplex PCR system for the simultaneous analysis of these loci with the automatic technology. This system was employed to obtain frequency data in the Tuscany population and to solve paternity dispute in which STR mutations were detected. A preliminary sensitivity study was also performed to evaluate the efficiency of this new duplex for stains analysis.