RAPD And Microsatellite Analysis Of Filial Generations From Cyprinus Carpio Var Specularis Lacepede (♀)×Carassius Curatus Cuvieri (♂) And Their Parents

In successive years of seedling and breeding in Wang Bin Fishing Ground of Xiangyin in Hunan Province, the first filial generation produced by a distant hybridization between Japanese Crucian Carp and German Mirror Carp always exhibits some hybrid vigor: an extremely fast growing speed, a strong resistance to diseases, a low population dispersion, etc. This experiment makes use of the Random Amplified Polymorphic DNA(RAPD) technique and micro-satellite technique to analyze the hybrids of Japanese Crucian Carp ((?))×German MirrorCarp ((?)) and their parents. From the angle of molecular genetics, we have detected the genetic relationship of Japanese Crucian Carp, German Mirror and their filial generations as well as the mechanism by which the hybrid is produced. Furthermore, the relative index obtained provides a reference for a quick selecting among relative species and feeding of new hybrids. Through selecting 24 valid objects from 112 random objects, the Random Amplified Polymorphic DNA (RAPD) analysis has been applied to Japanese Crucian Carp, German Mirror and their filial generations. The results demonstrate as follows: first, from a polymorphic loci analysis, the loci numbers detected from German Mirror Carp, Japanese Crucian Carp and F₁ are respectively 200,207 and 218, of which the polymorphic loci numbers are 63,66 and 72, with a proportion of 31.5%,31.9% and 33%. The result that the polymorphic loci of F₁ is considerately higher than that of the parents indicates that it has a diverse genetics and a highest level of variation. Second, from a genetic distance analysis, the genetic distances among these three species are 0.3068 (German Mirror Carp and Japanese Crucian Carp), 0.2041(German Mirror Carp and F₁) and 0.1961(Japanese Crucian Carp and F₁). The genetic distance between German Mirror Carp and Japanese Crucian Carp is the largest, which presumes that they have the strongest potential of hybridization. The fact that the genetic distance between F₁ and German Mirror Carp is higher than that between Japanese Crucian Carp and F₁ indicates a much closer relationship between Japanese Crucian Carp and F₁. Third, from a specific bands analysis, the specific band observed in Primer(S21) could be used as a molecular marker for discriminating German Mirror Carp from Japanese Crucian Carp as well as from F₁. And the specific bands observed in the Four primers (S79,S114,S331,S333) could be used as molecular markers for discriminating Japanese Crucian Carp from German Mirror carp and F₁. Another specific band observed in Primer(S106) could be regarded as a genetic marker for distinguishing F₁ from their parents. A phylogenetic tree which is constructed using Statistical Analysis System computer programme based on genetic distances clearly reveals that all individuals are clustered into three groups, which is reflected relationship among individuals.In this experiment, a total of 11 pairs of microsatellite primers have been screened for further analysis. The result demonstrates that a total of 119 different alleles have been found across the three populations by testing 11 micro-satellites, of which 36, 40 and 43 loci are detected in German Mirror Carp, Japanese Crucian Carp and F₁, and the mean number of alleles per locus are 3.27,3.64 and 3.91. Average numbers of alleles were 3.02,3.54 and 3.82. The observed heterozygosity values (H_o) are 0. 41,0.48and 0.53. The Average expected heterozygosity values (H_e) are 0.46,0.50 and 0.52 respectively. Therefore, the results from RAPD and microsatellite analysis were in agreement with each other, that is to say, F₁ presents drastically lower level of polymorphism than their parents and their parents' combination has a miscellaneous kind potential with an output advantage.