Xm System

Description

Berg and Bearn (1966, 1966) discovered an X-linked serum protein type by means of heteroantiserum made specific by absorption. Since the group-specific antigen appears to be located in the alpha-2-macroglobulin of serum, the name Xm was assigned to the system. The distribution of phenotypes in families and in populations was consistent with X-linkage.

Mapping

Berg et al. (1968) concluded that the Hunter syndrome locus (309900) and the Xm locus are within measurable distance of each other, the best estimate of the recombination fraction being 0.09. The strongest evidence of linkage was between Xm and deutan colorblindness (303800) where Berg (1969) found a lod score of 2.5 at recombination fraction of 0.05 and 0.10.