| Objective: Short tandem repeat (STR), also named microsate- llite DNA, has been widely used in phymatology,anthropology and forensic science, etc. because the short tandem repeat loci are widely dispersed in the human genome, easy to be detected and have high polymorphism. At present, short tandem repeat has been proposed as highly helpful tools for science of medicolegal physical evidence. Generally, the widely used STR loci are located on autosome and are suitable for most of the personal identification and paternity cases. But for some special cases such as paternity cases where the putative father is lacking;sexual assault cases containing a mixture of male and female DNA; tracing human migration and evolution through male lineage, autosomal STRs can not provide enough information. While, the human Y-chromosome have the special features of father-to-son transmission pattern, therefore, it can provide more information than the autosomal does in the above-mentioned cases. Y-chromosome STR can supply a new tool for personal identification and paternity cases and has special practical value. However, different regions and races of ethnic group have different gene frequency distributions, so before forensic applications, it is necessary to acknowledge the genetic information of Y-chromosome STR loci. In order to provide basic data of Hebei Han population, supplement the genetic database of China and enrich the data of group inherity and human migration and evolution, we investigated the genetic information of seven Y-STR loci including DYS19, DYS385, DYS389, DYS390, DYS635, DYS713 and DYS720.Methods:We studied 126 unrelated healthy males selected at random from the Hebei Han population, the genome DNA was extracted from whole blood samples by the method of phenol- chloroform extraction. The families and rotten materials samples came from routine paternity cases (father and son), and the genome DNA was extracted using Chelex-100 method. DYS19, DYS385, DYS389, DYS390, DYS635, DYS713 and DYS720 fragments were amplified and the amplified products were carried out by electrophoresis on a 6% denaturing polyacry- lamide gel (Acr:Bis=29:1). Bands were visualized by silver staining. We observed the polymorphisms of haplotype and assigned the alleles according to the recommendated principles of International Society of Forensic Genetics Commission after sequencing.Results: The genetics parameters of the seven loci: in the 126 unrelated individuals of Hebei Han population, 6 alleles were found in the DYS19 locus; 13 alleles and 49 genotypes were found in the DYS385; 4 alleles in the DYS389â… ; 7 alleles in the DYS389â…¡; 7 alleles in the DYS390; 9 alleles in the DYS635; 7 alleles in the DYS713 and 12 alleles in the DYS720. The allele frequencies of DYS19, DYS385, DYS389â… /â…¡, DYS390, DYS635, DYS713, DYS720 were 0.7492,0.9743,0.6380/0.7425,0.6857,0.7746,0.7533,0.8631, respectively.The haplotype frequencies of the seven loci : A total of 125 different haplotypes were observed, of which 124 were found in single individuals, one haplotype was found twice. The overall haplotype diversity was 0.9999476.The stability of heredity of the seven loci: The results of 5 family analysis showed that all the bands coincided with each other between father and son, which demonstrated that the father could transmit his alleles stably to his son.The identity character of the seven loci: Rotten materials of different tissues in the same cadaver were analyzed and demonstrated that each locus have the same allele. The 7 loci are all available to the standards of the forensic DNA analysis.Conclusions: The findings first provided the genetic data at DYS19, DYS385, DYS389, DYS390, DYS635, DYS713 and DYS720 loci in Hebei Han population. Gene fragments were short and easy to be amplified. All the seven loci showed the high polymorphism, sensitivity and specificity. With these characteristics, DYS19, DYS385, DYS389, DYS390, DYS635, DYS713 and DYS720 loci can provide a potential tool for individual identification and paternity testing in Hebei Han population.
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