| Two type molecular markers, randomly amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), were used to detect the genetic diversity between wild and cultivated populations of Olive flounder. ISSR was also used to detect the genetic structures of 3 wild populations and differences between "large" and "small" groups in the offspring of pair mating experiment. The results were as follows.1: RAPD and ISSR analyses were used to detect the genetic diversities in wild and cultured populations of the Olive flounder. Using 10 RAPD primers, a total of 110 reproducible loci ranging from 200 to 2500bp were amplified from 60 individuals. The percentages of polymorphic loci in wild and cultured populations were 59.09% and 60.90%, while the Shannon's indices were 16.563 and 16.917, respectively. The intra-population genetic distance was 0.17427 in wild and 0.17553 in cultured population. The averaged genetic distance between the two populations revealed by RAPD analysis was 0.17419. In ISSR analysis 161 loci were obtained from the 60 individuals, of which 111 (68.94%) in wild population and 112 (69.57%) in cultured population were polymorphic loci. The Shannon's indices were 0.1817 and 0.1844, and the intra-population genetic distances were 0.19996 and 0.20068 in wild and cultured populations, respectively. The averaged genetic distance between the two populations revealed by ISSR analysis was 0.20002. By μ value test no significant differences between the two populations in the average percentage of polymorphic loci, indicating little genetic differentiation in the cultured population.2: ISSR was used to detect the genetic diversity of three geographical populations of Olive flounder. The samples were from Weihai (China, W), Tottori (Japan, J) and Yosu (Korea, K), respectively. Seventy-nine individuals from three populations weresampled .Of the 60 primers screened, 10 produced highly reproducible bands. Using these primers a total of 263 discernable fragments ranged 200-3 OOObp were generated. Population specific loci were not observed in all the 3 populations. The average percentages of polymorphic loci in the three populations were 64.26% (W), 61.22% (J) and 59.20% (K), respectively. The genetic distances and genetic similarities within and among populations were calculated by binary matrix. The results demonstrated that the genetic diversity of W population was the highest of the three populations, while H population was the lowest. At the same time we found the distance between W and J was the farthest by calculation (0.1381). The genetic diversity level revealed by the average percentages of polymorphic loci and the Shannon diversity index in the three populations was W>J>K. However, the genetic structures of the three populations were not significantly differentiated form each other.3: Five ISSR primers were used to amplify the "large" and "small" groups derived from offsprings of two pair mating experiments. Three group specific loci were generated by primer 841 in "large" individuals only. Another loci by the same primer showed significant difference in frequencies between the "large" and "small" groups. Amplification using other primers did not show significant difference between the two groups. The above different fragments were purified, cloned and sequenced. Sequence specific primers were designed to amplify the satellite sequence from genomic DNA, but the sequences obtained did not contain the expected satellite. Furthermore, amplifications using primer 841 in "large" and "small" populations from group mating did not exhibit the above four loci, which indicated that the four loci existed in the parents of pair mating only.
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