SIMULTANEOUS DETERMINATION OF STR POLYMORPHISM AND A NEW NUCLEOTIDE SUBSTITUTION IN ITS FLANKING REGION AT THE CD4 LOCUS

In the course of the investigation of a pentanucleotide repeat polymor phism at the human CD4 locus, a C-A transversion was found at the posi tion corresponding to the 3' end of the original forward primer presen ted by Edwards et al. (1). In the present study, the simultaneous dete rmination of the new sequence polymorphism and the pentanucleotide rep eat polymorphism at the CD4 locus was attempted. To achieve this purpo se, we adopted amplified product length polymorphism (APLP) analysis a nd designed some new allele-specific forward primers tag,oed with non- complementary nucleotides differing in length. A total of 646 DNA samp les from peripheral blood of Japanese, Chinese and German populations were investigated. Although the C-A transversion was restricted to CD4 5, a new subtype allele with A and 5 repeats, designated CD4*5A, was observed at polymorphic frequencies in the three populations. The simu ltaneous genotyping by APLP analysis resulted in dramatically increase d heterozygosity and discriminating power of the human CD4 locus.