Shared synteny of human chromosome 17 loci in Canids

Canids are unusual among mammals in the large degree to which their karyotypes have diverged during speciation. In many instances, chromosome segments from different species share cytogenetic homology, and a presumed phylogenetic tree of Canid evolution can be constructed based on the relative shuffling of chromosomal elements. In this study, four gene probes (myeloperoxidase [MPO], Miller-Dieker [MDCR], ERBB2, and retinoic acid receptor a [RARA]) from human chromosome 17 were used in fluorescence in situ hybridizations with chromosomes of three different Canids: two subspecies of the Asiatic raccoon dog (Nyctereutes) and the domestic dog (Canis familiaris). The Nyctereutes subspecies have widely diverged karyotypes (2n = 38 versus 2n = 54) and Canis familiaris has a large number (2n = 78) of chromosomes. This study confirms the identity of two shared chromosomes of Nyctereutes. The Japanese raccoon dog chromosome 13 shares linkage with the Chinese raccoon dog chromosome 5. Both of these Nyctereutes chromosomes share synteny with human chromosome 17. Human chromosome 17 shares linkage with Canis familiaris chromosome 23. The relative order and spacing of the genes mapped in these species suggests the occurrence of chromosome rearrangements, most notably inversions, during the evolution of these animals.