Assignment of retinal dystrophy (rdy) to linkage group IV of the rat

The retinal dystrophy gene, rdy, in the rat displays autosomal linkage of 19.0 +/- 1.7 percent with nonagouti, a, and 31.8 +/- 4.1 percent with Svp-1 in linkage group IV. The data are consistent with the linear order rdy--a--Svp-1, but the orientation of this sequence with respect to the centromere is not known. A congenic strain has been developed from some of the testcross animals in which retinal dystrophic and heterozygous control rats of both pink-eyed and black-eyed phenotyped can be distinguished with pigmentation marker genes.