CHROMOSOME-NUMBER OF SEVERTZOVS SHEEP (OVIS AMMON SEVERTZOVI) - G-BANDED KARYOTYPE COMPARISONS WITHIN OVIS

Severtzov's sheep (Ovis ammon severtzovi; Nasonov 1914) has a 2n = 56 diploid chromosome number and a karyotype consisting of two pairs of b iarmed and 25 pairs of acrocentric autosomes, a large acrocentric X, a nd a minute biarmed Y. The G-banding patterns of the largest pair of b iarmed chromosomes were identical to those of the largest biarmed chro mosomes in all wild and domestic sheep of the genus Ovis. The banding patterns of the second pair of biarmed chromosomes were identical to t he third pair of biarmed chromosomes in all sheep of the genus Ovis wi th 2n = 54 and to the third largest pair of chromosomes in the 2n = 52 karyotype of the Siberian snow sheep (O. nivicola). The G-banded kary otype of Severtzov's sheep is consistent with all subspecies of argali (O. ammon spp.) that have been karyotyped. Numerical ascription of ac rocentric chromosome equivalents based upon the fundamental karyotype of Ovis that gave rise to the biarmed chromosomes of severtzovi are 1 and 3, and 5 and 11 for the largest and second largest biarmed chromos omes, respectively. Based upon diploid chromosome number and G bands, Severtzov's sheep should be considered a subspecies of argali and not a urial.