“…The compartmentalization of the species into breeds, together with the relatively short generation time of the dog (2-3 years), offers the potential of cloning genes not only using linkage analysis but also using identity by descent studies in sporadic cases. Disorders as diverse as narcolepsy (Mignot et al, 1991;Kadotani et al, 1998), Duchenne muscular dystrophy (Cooper et al, 1988), von Willebrand disease (Thomas, 1996), lupus erythematosus (Teichner et al, 1990), immunodeficiencies Ameratunga et al, 1998), retinal degeneration (Acland et al, 1998), Xlinked nephritis (Zheng et al, 1994), congenital heart disease (Patterson et al, 1993), and various metabolic disorders Skelly et al, 1996;Victoria et al, 1996;Kishnani et al, 1997;Ray et al, 1998) have been reported to segregate in dog pedigrees. In several cases, candidate gene approaches have led to the isolation of genes homologous to those observed in the corresponding human disorders (Cooper et al, 1988;Henthorn et al, 1994;Zheng et al, 1994;Smith et al, 1996;Skelly et al, 1996;Thomas, 1996;Victoria et al, 1996;Kishnani et al, 1997;Ameratunga et al, 1998;Ray et al, 1998).…”