AN EXTENDED NOMENCLATURE OF THE CANINE KARYOTYPE

In contrast to many other animals, knowledge about the canine karyotyp e is quite sparse. This is due in part to the rather difficult canine karyotypic pattern. Except for the X and the Y chromosome, there are o nly acrocentric chromosomes, which appear to be quite small and diffic ult to identify unambiguously. In previous reports, schematic represen tations of the canine karyotype have been described. However, a nomenc lature comparable to that of the human karyotype or the karyotypes of sheep, cattle, or goats does not yet exist for the dog. Based on high- resolution banding of metaphase chromosomes from canine fibroblasts, w e propose an ideogram of the canine karyotype with 460 numbered bands and characteristic landmarks. In addition, the centromere positions of the canine chromosomes are determined by a combined GTG-banding/FISH approach, and the R- and G-banding patterns are compared.