Abstract

A family is described in which benign Becker type X-linked muscular dystrophy and deutan colour blindness are segregating. The lod scores from this family have been added to those obtained in a family previously reported (Emery et.al, 1968/1969) and give an estimate of 0·23 for the recombination fraction with 95% confidence limits of 0·13 to 0·43. These results confirm the linkage relationships between deutan colour blindness and Becker muscular dystrophy but since the loci for Duchenne muscular dystrophy and colour blindness are not within measurable distance of each other these results indicate that the Becker and Duchenne types of X-linked muscular dystrophy are not allelic.