Haptoglobin genotyping by allele-specific polymerase chain reaction amplification

Abstract

We performed haptoglobin (Hp) genotyping by polymerase chain reaction using allele-specific primer-pairs. The major six genotypes of Hp were identified using this method. Among Japanese individuals living in Ehime and Okayama Prefectures, the allele frequencies were estimated to be Hp2 = 0.723 and Hp1s = 0.277. Genotyping of Hp was possible with 0.3 ng of DNA and with 0.125 microliter of blood. It was also possible with whole blood left at room temperature for a month and also with the bloodstains left at room temperature for three years. In the heated blood samples, both alleles, Hp2 and Hp1s, were detected in those heated at 100 degrees C for 2 h. In bloodstains, Hp2 and Hp1s were detected in samples heated at 100 degrees C for 2 h and 120 degrees C for 30 min. In addition, the genotype could be detected in samples other than blood such as saliva, hair roots, tissue sections and dental pulps. The present method for Hp genotyping is expected to become a useful method in forensic analysis.