Abstract: Objective To investigate the genetic polymorphism in the 5′ and 3′ region of TPH2 gene of Northern Chinese Han population and to explore its application value in forensic medicine. Methods The sequence variants and the genetic polymorphisms of 6 SNP loci （rs4570625, rs11178997, rs11178998, rs41317118, rs17110747 and rs41317114） within a 905 bp 5′ flanking region and a 1 104 bp 3′ flanking region of TPH2 gene were analyzed by DNA sequencing in a total of 244 unrelated healthy individuals in Northern Chinese Han population. The statistical analysis was carried out by Haploview v4.2 software. Results The genotypic distributions of the 6 SNP loci in the TPH2 gene were in accordance with Hardy- Weinberg equilibrium. One C/T variant in 92922 site was found. There was a high linkage disequilibrium among the 3 SNP loci （rs4570625, rs11178997 and rs11178998） in the 5′ region and the 3 SNP loci （rs41317118, rs17110747 and rs41317114） in the 3′ region of TPH2 gene, respectively. The parameters of population genetics of 6 SNP loci were obtained. Conclusion There are great polymorphisms in the 5′ and 3′ region of TPH2 gene in Northern Chinese Han population, which could be used as genetic indexes for association analysis of the related diseases, as well as for forensic individual identification and paternity testing.

Key words: forensic genetics, polymorphism, single nucleotide, tryptophan hydroxylase, Han population