Abstract: Objective To set up the method for analyzing HLA-B gene polymorphism with PCR-RFLP, and to gain population data among northern Chinese Hans of HLA-B′s restricted fragments after NlaIII digestion, and to achieve application in forensic medicine practice. Methods Sample DNA was extracted by the phenol/chloroform extraction method, 943 bp-long fragments containing HLA-B exon 2 and 3 were got by PCR. The endonuclease NlaIII was applied to cut the PCR products into polymorphic fragments shorter than 943bp, then PAGE and silver staining were used to detect the digestion results, finally the digestion sites were assured by DNA sequencing. Results Along 943bp-long PCR products, 14 length-different fragments, 20 kinds of fragment combinations were got and 6 cutting site were observed after NlaIII digestion. Conclusion HLA-B gene was highly polymorphic among Chinese northern Hans. Even with only one endonuclease, 14 restricted fragments were got and the PIC was great. Such a HLA-B PCR-RFLP analysis will have values in forensic medicine applications.

Key words: HLA-B gene, restriction fragment length polymorphism, discrimination power