IDENTIFICATION OF A RAPD MARKER LINKED TO PROGRESSIVE ROD-CONE DEGENERATION IN DOGS

Random amplified polymorphic DNA (RAPD) analysis has been used widely in plant and fungi for identification of markers linked to genetic tra its and mapping, but its use is limited to identification of intra- an d inter-species difference in domestic mammals. We report here identif ication of a RAPD-derived marker Linked to progressive rod-cone degene ration (prcd), an inherited autosomal recessive retinal disease of dog s. A total of 400 standard 10-mer primers were used for amplification by use of DNA samples from normal (+/-) and affected (prcd/prcd) dogs. A single primer was identified which amplified a 1.5-kb DNA fragment only from normal dogs. PCR with longer primers designed from the seque nce-characterized amplified region of the 1.5-kb DNA fragment identifi ed a co-dominant multi-allelic polymorphism in the prcd-informative pe digree. Three recombinants were identified among 34 informative offspr ings, yielding a LOD score of 5.568 at theta = 0.091. This marker was mapped to two canine-rodent hybrid cell lines in which two genes (cani ne homologues of human breast cancer 1 susceptibility gene, and cGMP p hosphodiesterase gamma-subunit gene), and three anonymous microsatelli tes have been identified. This is the first reported identification of a RAPD-derived marker with multiple alleles linked to a mammalian dis ease locus.