Japanese population study of a Y-linked dinucleotide repeat DNA polymorphism

Pt polymorphic CA repeats (YCA II) was previously reported on the human Y c hromosome. We have used a simple technique based on polymerase chain reacti on amplification followed by native polyacrylamide gel electrophoresis to s tudy the inheritance, the genetic stability, and the allele frequency distr ibution of this polymorphism in the Japanese. We found seven haplotypes whi ch were tentatively designated as: A[(CA)19/(CA)21], B[(CA)19/(CA)22], C[(C A)19/(CA)23], D[(CA)19/(CA)19], E[(CA)21/(CA)21], F[(CA)22/(CA)22], and G[( CA)23/(CA)23]. The frequencies of these haplotypes were: A, 0.21;B, 0.29; C , 0.37; D, 0.02; E, 0.02; F, 0.07; G, 0.01. There was complete concordance with each father-son pairs. The results indicate the dinucleotide system YC A II is very useful for investigation of forensic samples, especially mixed stains in sexual offence cases.