Genetic polymorphism of human salivary proline-rich proteins: Further genetic analysis

Electrophoresis of concentrated parotid saliva on slab polyacrylamide gels negatively stained with 3,3-dimethoxybenzidine and hydrogen peroxide (DMB stain) showed nine phenotypes among the proline-rich proteins. These phenotypes are the expression of four autosomal codominant alleles. Gene frequencies are, for Caucasians, Pr¹=0.640, Pr¹=0.005, Pr²=0.080, Pr²=0.275; for Negroes, Pr¹=0.700, Pr¹=0.050, Pr²=0.080, Pr²=0.170; for Chinese, Pr¹=0.770, Pr¹=0, Pr²=0, Pr²=0.230. The presence or absence of another pair of proteins giving the same negative staining is inherited as an autosomal dominant trait (Db). Homozygous Db + + and heterozygous Db + – individuals could not be distinguished. The genetic determinant (Db) for this pair of proteins is either closely linked to or part of the Pr locus. Gene frequencies are, for Caucasians, Db⁺=0.12, Db^–=0.88; for Negroes, Db⁺=0.56, Db^–=0.44; for Chinese, Db⁺=0.07, Db^–=0.93.This study was supported by a grant from the National Institutes of Dental Research (9-R01-DE-03685-08) and in part by grant GM 15422 from the National Institutes of Health.