| Research Abstract |
In order to identify a suspect in sexual offenses, semen and semen-stains are one of the most important materials. At the present time, only two or three genetic markers in semen have been used for individual ization of them, although many more useful markers have been adopted for blood samples for the same purposes.
We found that genetic polymorphisms of deoxyribonuclease I (DNase I), transferrin (TF), alpha-1-antitrypsin (PI), and fucosidase (FUCA1) were the most appropriate for individualization tests from semen samples, because they have several excellent characteristics : nice gene frequencies, resistancy agaist denaturation, a large amount of their contents in semen, and highly sensitive and specific detection methods for their typing. Our research results about DNase I are as follows.
1. We discovered the genetic polymorphism of DNase I.DNase I is controlled by four co-dominat alleles, DNASE1^*1, ^*2, ^*3 and ^*4. The polymorphism was detected in Japanese, other Asiatics, Caucasians and Africans.
2. DNase I polymorphism were expressed in both body fluids (semen, urine, serum and saliva) and organs (pancreas, liver and kidney).
3. We elucidated the structural organization of the gene for DNase I and showed that the gene was ca. 3.2 kb long, it comprised 9 exons separated by 8 introns and its complete sequence was determined.
4. A regional localization of DNase I gene was assigned to 16p13.3 using the PCR.
5. All the four alleles of DNase I was generated by a point mutation (one nucleotide substitution) occured in the coding region. These substitutions resulted in the replacement of amino acid residues of the mature enzyme. Using two methods, mismatched PCR amplification and amplification refractory mutation system (ARMS), we succeeded in discriminating all of the four DNase I alleles.
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