Molecular evolution of centromere-associated nucleotide sequences in two species of canids

The major centromeric satellite nt sequences present in the domestic dog (Canis familiaris) and in the grey fox (Urocyon cineroargenteus) have been examined. The dog satellite monomer is 737 bp long and contains 51% G + C; the grey fox satellite monomer is 880 b long and contains 54% G + C. The two satellites share three regions of 78, 92 and 314 bp with 70-80% sequence similarity. Sequence data from 16 monomers of dog satellite and 19 monomers of grey fox satellite demonstrate that the substitution spectra are different in the two canid species. For example, substitutions involving G or C residues are much more common in the grey fox satellite than in the domestic dog satellite despite their similar G + C contents.