Objective: To investigate genetic polymorphism of three Y Chromosome short tandem repeat(Y-STR) loci(GATA-A7.2、GATA-C4、DYS437) in Chongqing Han and Tujia population.Methods: This study based on Han male gender 115

female gender 15

Tujia male gender 120

female gender 15 unrelated individual blood samples.DNA was extracted with Chelex method.Each DNA sample was amplified using PCR for GATA-A7.2

GATA-C4 and DYS437 locus.The PCR products of three Y-STR loci were analyzed by denaturing vertical polyacrylaminde gel electrophoresis with continuous buffer system

genotyping with silver stain method.Use direct counting method to calculate allele and genotype frequency

calculate gene diversity(GD)/haplotype diversity(HD) of three loci and compare two nationalities allele distribution feature.Results: We observed 5、5、3 alleles in locus GATA-A7.2、GATA-C4、DYS437 respectively

the GD values are 0.697 9/0.714 1、0.720 2/0.700 1、0.511 2/0.495 7(Han/Tu jia).44 haplotypes were found

the HD for the three Y-STR loci was 0.955 6 in Han and 0.953 2 in Tujia.There were no PCR products of three Y-STR loci for the female individual

it indicated that the three loci were specifically for the chromosome Y and there were no their homologous sequences on the chromosome X.Conclusion:It was suggested that GATA-A7.2

GATA-C4 and DYS437 locus are suitable for individual identification and paternity testing

and they provide new selectable STR markers for chromosome Y haplotype in forensic application.