Linkage relations of dumpy, a recessive mutant on chromosome 13 of the mouse.

A mutant characterized by small size, short snout, short middle and inner metatarsals and hallux, low vigor, and poor reproduction appeared in F2 from a cross of BALB/c in 1965. It proved recessive and was named dumpy, with symbol dpy. After some 10 years of maintenance, the stock showed much improved vigor and reproduction, but it is not carried on a pure-strain background. Linkage was found with satin (sa) in linkage group XIV, chromosome 13. Data from female heterozygotes gave about 16 percent crossing over, and from males about 10 percent. Three-point tests involving XtJ showed the map order XtJ-sa-dpy, again with sex difference in crossing over, confirming results of studies by others for this region of chromosome 13.