Abstract: Objective One multiplex genotyping system was developed in using silver staining with allelic lad - ders for three Y-chromosome STR markers(DYS434,DYS443,and DYS456),with a view towards the applica - tion of rapid and simple genotyping assay methods for DNA profiling.The distributions of haplotypes for three Y-STR loci(DYS434,DYS443,and DYS456)was investigated in a Tibetan ethnic group of Chinese population.Methods Allele and haplotype frequencies at these Y-STRs loci(DYS434,DYS443,and DYS456)were analysed by PCR amplification using Y-STR multiplexes,followed by horizontal non-denaturing polyacrylamide gelelec-trophoresis in101unrelated males of Tibetan ethnic group in Lasa of China.Results A total of31different haplotypes were found,16of them being unique.The haplotype diversity value(which is the same as the dis - crimination index)calculated from all three loci combined was0.9481,which is informative.Conclution The Y-STR multiplexes provide useful information for forensic analysis and paternity tests and can also be of great ben - efit for providing information not normally available from autosomal DNA systems.

Key words: Y chromosome, DYS434, DYS443, DYS456, STR, Tibetan ethnic group, haplotype