Evidence of duplication of the human salivary amylase gene.
Isoelectric focusing of human parotid saliva reveals different alpha-amylase patterns reflecting qualitative and quantitative variations. A puzzling pattern, which shows three different amylase gene products, was found in four individuals. Based on this observation a model is presented in which the salivary amylase gene is duplicated. Family studies show that the AMY1*A2 gene forms a haplotype with the normal gene, AMY1*A1, whereas the AMY1*A3 gene still exists in a single form. The absence of homozygote 2-2 in offspring of 1-2 X 1-2 marriages and in population material, and the fact that the variant protein makes up about only 20-30% of the total amylase protein in heterozygotes can be considered as additional evidence supporting the hypothesis. The possibility that cis-acting regulatory variants are involved in the patterns with quantitative variation is discussed.
D000681:Amylases / Q000235:genetics*; D002869:Chromosome Aberrations; D005260:Female; D005796:Genes; D014644:Genetic Variation; D006238:Haploidy; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D010375:Pedigree; D010641:Phenotype; D014176:Protein Biosynthesis; D012463:Saliva / Q000201:enzymology*; D000516:alpha-Amylases / Q000235:genetics*
D000681:Amylases; D000516:alpha-Amylases