Does the mouse C4-binding protein gene (C4BP) map in the H-2 region?

A previous study on the genetics of mouse C4-binding protein (C4-bp) indicated the existence of a genetic polymorphism. Two genetic variants were reported and their segregation used to determine the mapping position of the C4BP locus to the H-2D-Qa interval of the mouse H-2 system. We show here, however, that purified C4-bp does not display the previously reported polymorphism. The mapping position of C4BP in the mouse therefore remains undetermined.