A comparative chromosome map of the Arctic fox, red fox and dog defined by chromosome painting and high resolution G-banding

Abstract

A complete set of paint probes, with each probe specific for a single type of dog chromosome, was generated by DOP-PCR amplification of flow-sorted chromosomes. These probes have been assigned to high-resolution G-banded chromosomes of the dog and Arctic fox by fluorescence in-situ hybridization. On the basis of these results we propose improved nomenclature for the G-banded karyotypes of the dog and Artic fox. A comparative map between the Arctic fox, red fox and dog has been established based on results from chromosome painting and high-resolution G-banding. This map demonstrates that the euchromatic complements of these three canid species consists of 42 conserved segments. Thirty-four of these 42 segments are each represented by a single dog chromosome with dog chromosomes 1, 13, 18 and 19 each retaining two segments, respectively. The autosomes of the Arctic fox and red fox could be reconstructed from these 42 blocks in different combinations through chromosomal fusions. Our findings suggest that chromosome fusion has been the principal mechanism of karyotype evolution occuring during speciation in canids.