Comparative Analysis of the Karyotypes of the Greater Long-Tailed Hamster and the Chinese Hamster.

The G-, R-and C-banded karyotypes of the two hamster species, the greater long-tailed hamster (Cricetulus triton or Tscherskia triton) and the Chinese hamster (Cricetulus griseus), were analyzed. The diploid chromosome number of Chinese hamster is 22, and that of the greater longtailed hamster 28. These are morphological differences between two hamster species : the number of metacentric and submetacentric autosomes was only 4 in the greater long-tailed hamster, in contrast to 14 in the Chinese hamster, while the number of acrocentric and subtelocentric chromosome was 22 in the greater long-tailed hamster and 6 in the Chinese hamster. The analysis of banding patterns in the two hamster species revealed that each chromosome of the greater long-tailed hamster corresponded to one arm or one whole chromosome of the Chinese hamster. However, the large C-bands (or lightly stained with R-bands) such as those found around the centromeric region of the greaterlong-tailed hamster chromosomes did not exhist in the centromeric region, or any other segments, of any chromosome in the Chinese hamster. These findings may be related to the karyotypical evolution of the two hamster species, but it is difficult to say which these hamster species are belonged to the same genus Cricetulus or not.