Human immunoglobulin D segments: Isolation of a new D segment and polymorphic deletion of the D sub(1) segment

The authors have isolated and identified a new human germline D segment which is not physically linked to the known D cluster. The nucleotide sequence of the new D segment was highly homologous with the known D segments. Frequent polymorphic deletion of the D sub(1) segment was found in the Japanese population. Nucleotide sequences surrounding the deletion indicate that homologous recombination is likely to be responsible for the deletion of the D sub(1) segment.