Karyological Analysis of Two Species in the Subfamily Schizothoracinae (Cypriniformes: Cyprinidae) from China, with Notes on Karyotype Evolution in Schizothoracinae

Özet

The karyotypes of Schizothorax kozlovi and S. lissolabiatus in the Subfamily Schizothoracinae, both of which areendemic to China, were investigated for the first time using the methods of kidney cell culture in vivo, and the numbers, sizesand morphology of the chromosomes in the two species were expatiated. The karyotype formula of S. kozlovi could be statedas 2n=92 = 18M+14SM+16ST+44T, FN=124, and that of S. lissolabiatus might be described as 2n=148=44M+36SM+20ST+48T, FN=228. S. kozlovi was probably a tetraploid species while S. lissolabiatus should be a hexaploid one, both these twospecies should belong to the primitive group in Schizothoracinae.Almost all species karyologically investigated were polyploid including tetraploid and hexaploid in Schizothoracinae.The karyotypes in the subfamily might be originated from the primitive karyotype in Cyprinidae through approaches ofcentromere breakage, polyploidization and polyploidization with centromere breakage, Robertsonian translocation orchromosome deletion, under the pressure of rigorously natural selection in the Qinghai-Tibet Plateau. Also, the karyotypesevolved with the increase of number proportion of the metacentric (submetacentric) chromosomes in somatic cell of thespecies in Schizothoracinae.