Comparative Study of the Karyotypes of Several Species in Carnivora Including the Giant Panda (Ailuropoda melanoleuca)

Abstract
The chromosome morphology and the sex chromatin pattern have been investigated in Ailuropoda melanoleuca (giant panda) and a number of related animals. The following chromosome numbers have been determined: Ailuropoda melanoleuca, 42; Ursus americanus, 74; Selenarctos thibetanus, 74; Tremarctos ornatus, ?54; Canis familiaris, 78; and Chrysocyon brachyurus, 76. It is suggested on cytological grounds that there may be a close relationship between U. americanus, U. middendorfi, Thalarctos maritimus and S. thibetanus, but this does not include A. melanoleuca or T. ornatus. Nevertheless in taxonomy the morphology of the chromosomes, as known at present, must only be regarded as one of many differentiating factors. Sex chromatin has been seen in the female animals investigated but not in the male. The absence of the enzyme, alkaline phosphatase, from the neutrophils of S. thibetanus, and A. melanoleuca, but not C. brachyurus, is an interesting observation.