Canine genetic linkage study using heterologous DNA probes

We have used clones of 17 single-copy human DNA sequences to analyze their counterparts in the genome of the domestic dog by heterologous hybridization. Ten of the 17 sequences represented anchor loci proposed for comparative mammalian mapping. Eight of 17 human clones (including three of the anchor loci) gave clear hybridization signals when used with Southern blots of canine DNA. Five of these eight (including two anchor loci) showed diallelic restriction fragment length polymorphisms in a large kindred of Brittany spaniels and could be used for segregation studies. Several probes chosen from different human chromosomes also were unlinked in the dog. By contrast, linkage was found between the canine counterparts of the closely linked human serum amyloid A gene family. Three markers linked on human chromosome II appeared not to be syntenic in the dog. DNA markers linked to various human genetic neuromuscular diseases were not linked to hereditary canine spinal muscular atrophy which segregates in this kindred. However, there was evidence of possible linkage of this disorder with a canine counterpart of the tyrosinase gene. Segregation studies using heterologous single-copy DNA probes can be performed in dogs, but the level of inbreeding may reduce heterogeneity and limit the power of the analysis.