Confirmation of the assignment of the Dombrock blood group locus (DO) to chromosome 12p: Narrowing the boundaries to 12p12.3-p13.2

Background and Objectives: Antigens belonging to the Dombrock blood group s ystem have been well characterized serologically. Despite being reasonably polymorphic, chromosomal localization of the gene controlling Dombrock expr ession (DO) has proved difficult. In the past, DO had been provisionally as signed to chromosomes 1 and 4; more recently, DO was provisionally assigned to chromosome 12. The current study was undertaken in an attempt to confir m or refute this latest assignment. Materials and Methods: DNA from a series of families segregating for DO was amplified by polymerase chain reaction and analyzed for trinucleotide or t etranucleotide repeat polymorphisms of four anonymous DNA markers (D12S1042 , D12S373, D12S391, D12S372) and of the von Willebrand factor gene (VWF). L ods for or against linkage were determined between DO and each marker. Results: DOis linked to all five markers. The closest linkage was establish ed between DO and D12S373, and DO and D12S391, with peak lods for combined paternal and maternal meioses of 7.16 at peak recombination fraction (<(the ta)over cap>)= 0.08 and 7.69 at <(theta)over cap> = 0.08, respectively. Conclusions: We have confirmed the assignment of the Dombrock blood group l ocus to chromosome 12p and have refined its regional localization to 12p12. 3-p13.2. Copyright (C) 2000 S. Karger AG, Basel.