Studies On Karyotype Of Chinese Spined Loach (Cobitis Sinensis) And Its Polymorphism

Using the methods of classical shape size measuring and chromosome analysis, we studied the morphological characters and Karyotype of Cobitis sinensis in Xiangjiang River. We also investigated the evolution line and Karyotype polymorphism of the C . sinensis by the methods of cytological classification and cytocatalytic. Our results suggest that the formation of chromosome polymorphism was concerned with heterologous hybridization and some of C . sinensis may perpetuate in a clonal manner by natural gynogenesis.According to pigmentary zones of Gambetta, C . sinensis in Xiangjiang River is different from others like C . sinensis from Sichuan Guizhou Taiwan and Dongting Lake. It looks like C. macrostigma Dabry. The exact relationships among various geographical pupulation need more investigation rather than merely the evidence based on conformation.The chromosomal number and Karyotype of C . sinensis in Xiangjiang River was determined. The total chromosome number of the fish is 40, the karyotype formula is 2n= 20m+10sm+2st+8t, and NF=70.The basic diploid number of chromosomes in the family Cobitidae was deemed to 2n=50. The C . sinensis with 2n=40 may originate from the ancestor of the subfamily Cobitidae. The C sinensis with 2n=90 which reserved all of 40 original chromosomes maybe result from heterologous hybridization among some fishes of the subfamily Cobitidae. The C . sinensis with 2n=76 is probably a branch of hybrid offspring.After analyzing the mode of reproduction in some other loaches of natural polyploidy, we also assume that gynogenesis of C â–  sinensis with 2n=76&90 is of hybrid nature before the diploidization being completed.