Objective To establish a novel multiplex amplification system which comprises 24 Y-STR loci.Methods Total 24 Y-STR gene loci, concluding DYS531,DYS630,DYS622,DYS552,DYS510, DYS449, DYS459a/b, DYS446, DYS443, DYS635, DYS587, DYS527a/b, DYS460, Y-GATA-A10, DYS520, DYS557,DYS522,DYS481,DYS570,DYS385a/b,DYS444, were chosen for establishing the fluorescence multiplex amplification system. The specificity, identity, sensitivity, balance of the amplification, anti-in-terference and accuracy of the system were detected and the gene diversity was investigated in the popu-lation of Guangdong.Results No band was found in nonhuman and female samples that were tested by the established multiplex amplification system. The same genotyping results were obtained from different tissues of the same person. Complete profiles could be obtained from more than 0.1 ng of the standard sample 9948. The loss of alleles was found when the common inhibitors such as hemoglobin and calci-um ion were added 120-200μmol/L and 1.5-2.0 mmol/L respectively to the system which with a strong anti-interference to the indigo, humic acid and EDTA. The typing of 24 Y-STR system could give the reliable results when 146 unrelated male individuals were detected and compared with the Yfiler system parallelly. The haplotype diversity(HD)of the population in Guangdong reached 0.99972 that was better than the result retained from Yfiler system, which the HD was 0.99858.Conclusion The fluorescence amplification system with 24 Y-STR loci established in present study has a wildly application prospect and can be used for cases inspection, paternity tests and Y-STR database construction.

Objective To establisha multiplex STR genotyping m ethod for autosom al STR and Y-STR loci in forensic biological practice. Methods W idely used autosom al STR loci and Y-STR loci w ere se-lected. A set of PC R prim ers w as designed, and a 5-dye fluorescent labeled STR multiplex PC R reagent kit w as developed. Results A kit w as developed w hich can sim ultaneously detect 15 autosom al STR loci, 10 Y-STR loci, and an Amelogenin. Conclusion The 15 autosom al STR plus 10 Y-STR kit in com bination w ith capillary electrophoresis m ethod w as used to STR genotyping w ith accurate and reli-able results. The new one-step testing kit can potentially be w idely used in forensic cases and D N A databank in the future.