2 ADDITIONAL POLYMORPHISMS WITHIN THE HYPERVARIABLE MUC1 GENE - ASSOCIATION OF ALLELES EITHER SIDE OF THE VNTR REGION

The gene MUC1 codes for a mucin-type glycoprotein and like most of the other mucin genes shows variable number tandem repeat (VNTR) polymorp hism within the coding region. A polymorphism due to a G/A substitutio n in er;on 2, responsible for a genetically determined variation in sp licing of the MUC1 transcript, has also been reported (Ligtenberg et a l. 1990, 1991). Here we describe the detection of this nucleotide subs titution polymorphism by single stranded conformational analysis of ge nomic DNA and we also report a CA repeat polymorphism within intron 6 of the gene. Haplotypes were determined in a series of families and th e common alleles of these two polymorphisms were found to be associate d. These results support the notion that the VNTR polymorphism in the coding sequence of MUC1 is not caused by unequal reciprocal recombinat ion at meiosis.