Hayato Hasekura

Sequence polymorphism in the mtDNA HV1 region in Japanese and Chinese

We investigated the nucleotide substitution and insertion/deletion polymorphism of the HV1 region in mtDNA by sequencing blood samples from 150 unrelated Japanese and 120 unrelated Chinese and revealed 108 sequence types from the Japanese group and 87 sequence types from the Chinese. Some substitutions were characteristic of East Asian populations as compared with data reported on Caucasian populations, and some were area-specific among East Asians. The level of genetic diversity and genetic identity revealed by this system was superior to that obtained by VNTR systems for nuclear DNA. These results show the usefulness of mtDNA sequencing in forensic examination for individual identification. We also found some sequence variations in the homopolymeric tract of cytosine (np16180-16194 in the Andersons reference sequence) that might suggest some hints regarding the mechanisms for and the development of heteroplasmic length variations in this tract.

The HumD21S11 system of short tandem repeat DNA polymorphisms in Japanese and Chinese

HumD21S11 is a short tandem repeat DNA polymorphic system with a complex basic structure of (TCTA)4-6 (TCTG)5-6 (TCTA)3 TA (TCTA)3 TCA (TCTA)2 TCCA TA (TCTA)n. Using the allelic ladder prepared by us, the distribution of alleles among Japanese and Chinese was investigated, and four new alleles 28.2, 34, 35.2, and 36.2, were discovered. DNA sequencing was performed on the newly found alleles as well as on family samples and led to the discovery of different gene structures within alleles 28 and 32. Forensic materials, including hairs and seminal stains, were tested in parallel with blood samples from the same individual and were successfully typed for D21S11.

Immunohistochemical examination of the lungs in infant death cases using antibodies against milk components

To examine the use of immunohistochemical staining with antibodies against milk components for detection of aspirated milk on lung sections, eighteen infant death cases were investigated. Immunostaining was performed with anti-human alpha lactalbumin, anti-human IgA, anti-human milk fat globulin 1, and anti-cow whey antibody. Reactivity with each antibody was examined, and semi-quantitative examinations were performed to compare the amount of aspirated milk using anti-human alpha lactalbumin antibody. Materials in the alveoli or bronchioli on lung sections suspected to be aspirated milk showed the most sensitive and clearest reaction with anti-human alpha lactalbumin antibody. Of the eighteen cases, ten cases showed positive reaction with this antibody. The amount of aspirated milk varied widely in each case. In conclusion, immunohistochemical staining with antibodies against human milk components, especially anti-human alpha lactalbumin antibody, can detect small amounts of milk. Using this method, we were able to compare the relative amount of aspirated milk among cases.