Restriction fragment length polymorphism detected by human salivary amylase cDNA

The plasmid clone which contains human salivary amylase cDNA was used to detect restriction fragment length polymorphisms (RFLPs). After double digestion with Pst 1 and Bam H1, a polymorphism with two alleles was observed. In Japanese, frequencies of these alleles, tentatively called 5.7 kb and 6.5 kb fragment alleles, are 0.55 and 0.45, respectively.