× Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø × Ø

In Japanese forensic casework, high sensitive serological procedures including absorption elution method are adopted for ABO blood typing. However, in some cases the serological typing is confused for mixed fluid stain samples. Differential DNA extraction method and ABO typing using PCR and RFLP can be more effective for mixed stain of seminal and vaginal fluid when mixed types are obtained using the serological method.

In our experiment along with the report of Ladd et al., the region of nucleotide #261 deletion in O allele was less detectable than the region of nucleotide #703 substitution in B allele. So we checked their primer sequence and found that the sequence used by Ladd et al. from transferase sequence data of Yamamoto et al. did not include the sequence data of intron. In this report, we referred the intron sequence data of Bennett et al. and used a newly designed primer set for PCR amplification.

As a result, the deletion region of O allele could be amplified and detected as sensitive as the substitution region of B allele. And ABO typing could be done from smaller quantity of bloodstain samples by the new primer set than by original one.

And more, we tried to use ABI 310 genetic analyzer and fluorescently labeled primer set to analyze the ABO typing because short restriction fragment can not be clearly detected using Et-Br staining and agarose gel electrophoresis. By this method, we could get higher sensitivity and correctly detected the ABO typing of the casework samples.