Physical and linkage mapping of human chromosome 17 loci to dog chromosomes 9 and 5.

Genome mapping in the dog is in its early stages. Here we illustrate an approach to combined physical and linkage mapping of type 1 anchor (gene) loci in the dog using information on syntenic homology from human and mouse, an interbreed cross/backcross, and a strategy for isolation of dog genomic clones containing both gene-specific sequences and simple sequence repeat polymorphisms. Eleven gene loci from human chromosome 17q (HSA17q) were mapped to the centromeric two-thirds of dog chromosome 9 (CFA9), an acrocentric chromosome of medium size: P4HB, GALK1, TK1, GH1, MYL4, BRCA1, RARA, THRA1, MPO, NF1, and CRYBA1. Eight of these were also positioned on a linkage map spanning 38.6 cM. Based on combined fluorescence in situ hybridization and linkage mapping, the gene order on CFA9 is similar to that of the homologous genes on HSA17q and mouse chromosome 11 (MMU11), but in the dog the gene order is inverted with respect to the centromere. Canine loci, GALK1, TK1, GH1, MYL4, THRA1, and RARA constitute a closely linked group near the centromeric end of CFA9, spanning a genetic distance of only 4.7 cM. Canine NF1 and CRYBA1 lie distally, near the lower border of the Giemsa band adjacent to the distal one-third of CFA9. NF1 and CRYBA1 are loosely linked to the more centromeric group (31.2 cM). No HSA17 genes were found on the telomeric one-third of CFA9. Painting of dog chromosomes with a human whole chromosome 17 probe showed hybridization with only the proximal two-thirds of CFA9, consistent with the conclusion that the distal one-third corresponds to a segment or segments of other human chromosomes. Two loci, GLUT4 and PMP22, located on HSA17p, were mapped by FISH to dog chromosome 5 in a region also identified by the whole human chromosome 17 paint, indicating disruption of HSA17 syntenic homology at the centromere.