Chromosome evolution of the blue sheep/bharal (Pseudois nayaur).
A male dwarf blue sheep was collected 60 km south of Batang east to the Jinsha Jiang river, and a male Subei blue sheep (Greater form) was collected from Gansu, China, representing two geographically separated blue sheep forms. Chromosome preparations were prepared from fibroblast cultures. The dwarf blue sheep has a 2n = 54 and a karyotype with three biarmed formations that resulted from acrocentric chromosome fusions (based on the 2n = 60 Capra autosomal equivalents) 14p/5q, 27p/1q, and 29p/2q from the largest to the smallest biarmed chromosome, respectively. The 14p/5q fusion is metacentric, whereas the 27p/1q and 29p/2q are submetacentric. The Subei blue sheep had a 2n = 56, with only the 27p/1q and 29p/2q biarmed chromosome fusions. The remainder of the chromosomes in both blue sheep are acrocentric; the X is the largest acrocentric chromosome and the Y is a minute biarmed chromosome. Our observation is one evidence showing that chromosome evolution within blue sheep has followed a series of centric fusions resulting in the reduction of chromosome number, which is typical of all extant genera within the tribe Caprini.
Bunch
T D
TD
Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan 84322-4815, USA. tombunch@cc.usu.edu
Wang
S
S
Zhang
Y
Y
Liu
A
A
Lin
S
S
D000818:Animals; D005075:Biological Evolution; D002871:Chromosome Banding / Q000662:veterinary; D002875:Chromosomes; D007621:Karyotyping; D008297:Male; D012756:Sheep / Q000235:genetics*