Sequence analysis of alleles at a microsatellite locus D14S299 (wg1c5) and population genetic comparisons

In order to increase the discriminating power of DNA analysis in personal identification, we evaluated the forensic utility of the microsatellite locus D14S299 (wg1c5) in the Japanese population and also in the Chinese and Caucasian populations. Twelve different alleles were identified in length by gel electrophoresis with silver staining. The major alleles in Japanese were sequenced and designated as the numbers of the variable repeats (GGAT or GGAA). There were five variable regions and extensive homoplasy was found. However, the allele fragment lengths were in 4 bp increments and no "interalleles" were found. The estimated heterozygosity and the polymorphism information content (PIC) were 0.726 and 0.689, respectively in Japanese. Those in Chinese (0.743 and 0.704) were similar to those in Japanese, while those in Caucasians (0.812 and 0.781) were much higher. After adjacent alleles were combined to yield at least five entries, statistical analysis was performed. The power of discrimination (PD) was 0.887 in Japanese, 0.895 in Chinese and 0.935 in Caucasians and no significant deviations from the Hardy-Weinberg equilibrium were found in the three populations. We retyped all apparently homozygous samples using an alternative pair of flanking primers and found them to be true homozygotes. D14S299 appears to be a useful STR locus for forensic practice.