Genetic analysis of the short tandem repeat system D12S391 in the German and three Asian populations

Genomic DNA samples from 222 individuals from Southern China, 154 individuals from Thailand, 100 individuals from Japan as well as from 124 German individuals were analysed for the short tandem repeat (STR) locus D12S391. Typing was carried out by polymerase chain reaction (PCR) amplification and subsequent polyacryramide gel electrophoresis and silver staining. In total, 12 alleles could be distinguished in two of the populations. Among Chinese, allele 19 is the most common with a frequency of 0.225, and among Germans, allele 18 with a frequency of 0.186. In the Thai population only 11 alleles could be distinguished and allele 19 is the most common with a frequency of 0.198. In Japanese, two previously unknown alleles 27 and 28 were detected, 14 alleles could be distinguished, and allele 18 is the most common with a frequency of 0.295. The expected exclusion chance for Chinese, Thai, Japanese and Germans in paternity cases is 0.67, 0.71, 0.67 and 0.75, respectively, and the discrimination power in identification cases is 0.95, 0.96, 0.95 and 0.97, respectively. Testing of the observed genotype distributions for Hardy-Weinberg equilibrium did not reveal any significant deviations. Segregation studies of 124 meioses among German families did not reveal any mutations at the D12S391 locus. In casework studies two variant alleles were detected with a trimeric repeat each (17.3 and 18.3), which have been confirmed by sequencing.