[Repeat structure of DYS389 locus].

In the DYS389 locus, tetranucleotide repeat units (CTGT and CTAT) connect complicatedly, and repeat sequences to show polymorphism are found in two sections. Because non-repetitive sequence including the same sequence as forward primer exists among these repeat sequences, a pair of primers for the DYS389 locus give two amplification products (DYS389 I and DYS389 II), both of which are polymorphic. These polymorphisms come from the differences in the number of CTGT and CTAT repeats. DNA was extracted from the dental pulp of 68 males and saliva of 48 males, and amplified for the DYS389 locus. And then the length polymorphisms and the repeat structures were examined. As results of denaturing polyacrylamide gel electrophoresis, alleles 8-12 appeared in the DYS389 I locus, while alleles 24 29 appeared in the DYS389 II locus, with alleles 11 and 27 showing the most frequent. As results of sequencing of many samples, we confirmed that the repeat structures of the DYS389 I and II alleles were (CTGT)3 (CTAT)r and (CTGT)p (CTAT)q (CTGT)3 (CTAT)r, respectively. DYS389 I alleles were related to the repeat numbers of r (r = 8-12), and DYS389 II alleles to the repeat numbers of p + q + r (p = 4.5; q = 11-14; r = 8-12). Even the same DNA size of DYS389 II alleles had different repeat structures, indicating that DYS389 is effective for the purposes of individual identification and paternity testing.