| Leuciscus merzbacheri belongs to Cypriniformes, Cyprinidae, Leuciscinae, Leuciscus cuvier, also known as Xinjiang Leuciscus. In the division of the world geographical distribution, Leuciscus merzbacheri is the unique indigenous fish in Xinjiang, and only found in the Junggar Basin of Xinjiang Tianshan northern river systems.The food value of the fish has high nutrition, which formerly was the main economical fish in production areas, and has huge prospects for artificial breeding. Since many years,because of various reasons, the natrual resources of Leuciscus merzbacheri has been declining, its extant number is already extremely scarce, and faced with endangered condition,Therefore, it has the important scientific research value. In this paper, the study on genetic diversity of the karyotypes and banding patterns of them has not been reported thus far. Based on these current status, the chromosome karyotype and banding patterns of Leuciscus merzbacheri were studied and compared,which were collected from Jinghe and Kuitun regions.In this study, the chromosome karyotype and banding patterns of Leuciscus merzbacheri, which were collected from Jinghe and Kuitun regions, were compared by karyotype technique, Ag-NORs, C-Band and G-Band so as to analyze the variation on the level of cytogey (chromosome), We preliminarily analyzed the chromosome diversity of L.merzbacheri.The chromosome specimens of Leuciscus merzbacheri were obtained from metaphase of head kidney and kidney cells by colchicine-low concentration-air drying technique, and then studied their Giemsa stain, Ag-NORs, C-Band and G-Band were studied in this paper, The main results of the study were as follows:1 L. merzbacheri from Jinghe and Kuitun had a diploid chromosome number of 2n=50 and its karyotype formula was 18m+14sm+6st+12t, NF= 82, sex chromosome was not found. The possible evolutionary relations in chromosome were discussed among Leuciscus merzbacheri, Leuciscus baicalensis and Leuciscus idus.2 The Ag-NORs polymorphisms of L. merzbacheri from Jinghe were individually specific,1-2 of the number, and the frequency of 1 Ag-NORs was the lowest(10%), while the frequency of 2 Ag-NORs was the highest(70%).The main Ag-NORs polymorphisms were located in the short arms of the chromosome m1 and m4. The Ag-NORs polymorphisms of L. merzbacheri from Kuitun were individually specific,1-2 of the number, and the frequency of 1 Ag-NORs was the highest (68%),while the frequency of 2 Ag-NORs was the lowest t(25%). The main Ag-NORs polymorphisms was located in the short arms of the chromosome m3. The associations of Ag-NORs were not observed. The possible evolutionary relations in chromosome were discussed, and the resons of the difference were also discussed. The results showed:L. merzbacheri from Jinghe had a higher evolutionary degree.3 There were some differences in the C-banding patterns among populations in Jinghe and Kuitun,which included the different location and number of C-band. There were 1～4 C-bands on the chromosomes of L. merzbacheri,2 for the most ones. The C-banding pattern was mainly consisted of centromeric band,telemtric band and intercalary band. The results showed:L. merzbacheri from Jinghe had a higher evolutionary degree, which was accordance with the results of Ag-NORs study.4 There were some differences in the G-banding patterns among populations in Jinghe and Kuitun, which included the different location, number and width of C-band.The G-band in homologous chromosomes were basically coincident, and distinctive charaters of banding numbers and distributions could be identified in every homologous chromosome.In this paper, we preliminarily discussed the chromosome diversity of L.merzbacheri by cytogenetic methods, which not only provided the scientific basis for conservation of species, genetic breeding, evolution, rational development and utilization to Lmerzbacheri species, also provided great significance to the Xinjiang region of protection of other Leuciscus diversity. |
PDF Full Text Request