[Genetic polymorphism at D20S161 locus in Chinese populations]

To understand the genetic relationship between different populations in China and to obtain the preliminary data on the genetic poly- morphisms of D20S161 in seven populations in China.

EDTA-blood specimens were collected from 753 healthy unrelated individuals in seven Chinese populations, including Chengdu(Han), Guangzhou(Han),Jilin(Han),Lasa (Tibetans),Dali(Bai), Nanning(Zhuang) and Hailaer(Menggu),respectively. DNA was extracted with Chelex method. The DNA samples were amplified by PCR technique, and the PAGE horizontal electrophoresis was used for typing the PCR products.

Seven alleles at D20S161 locus were observed in six populations,while six alleles at D20S161 were observed in one population in Dali(Bai). The numbers of genotypes observed were 25, 19,21,19,16,20 and 22 for Chengdu(Han), Guangzhou(Han), Jilin(Han), Lasa(Tibetans), Dali(Bai), Nanning(Zhuang)and Hailaer(Menggu), respectively. The allele frequencies were D20S161*16:0.0220-0.0657, D20S161*17:0.1429-0.2947,D20S161*18: 0.3237-0.4835. D20S161*19:0. 0909-0.1850,D20S161*20:0.1263-0.1786,D20S161* 21: 0.0421-0.1010, D20S161*22:0-0.0250.A total of 26 genotypes were observed in 753 individuals. The heterozygosity was between 65.31% 80.41% for the seven populations. The results of test for Hardy-Weinberg equilibrium showed that the genotype distributions observed were correspondent with the expected.

There are seven alleles in Chinese populations, of which D20S161*18 is most frequently observed. No significant difference in the distribution of allele frequencies at D20S161 (X2=57.9342,P>0.01) was noted among the seven Chinese populations. D20S161 may be a very useful genetic marker for both paternity test and personal identification of casework in forensic medicine and for the purpose of population genetics.