| Turbot is one of our country’s main economic species in aquaculture, has brought about huge economic benefits. Experiments on genetic breeding in turbot were studied. In order to develop the EST-SSR markers of turbot, the transcriptome of turbot were analyzed and the microsatellite sequence were preliminary screened by establishing c DNA library and sequenced restructuring. After sequencing, 71107 Unigene were obtained, and 39430 SSR-containing sequences were screened from them :which containing single nucleotide repeats 18013, two nucleotide repeats 8388, three nucleotide repeats 8241, four nucleotide repeats 1518, five nucleotide repeats 1848, six nucleotide repeats 1197, seven nucleotide repeats 225. There are 4251 sequences can be designed for SSR primer. 210 primers were designed,150 of them had the purpose bands, 19 pairs were polymorphic. These results provide valuable information for the development of turbot EST-SSR markers. In this study, the segregation patterns of genotypes constituted by 70 microsatellite loci were analyzed in turbot parents and their progenies. The results indicated that a total of twelve patterns were detected through sexual hybridization(♀ × ♂). There were forty-five loci in accordance with Mendel’s law of inheritance(P≥0.05), while the rest 25 deviated from the law(P <0.05). The average number of alleles was 2.2; the average effective number of alleles was 1.885. The average expected and observed heterozygosity were 0.55 and 0.537, respectively. The range of polymorphic information content(PIC) was between 0.182 and 0.699, with an average of 0.361. The range of Fis was between-0.859-0.957,with an average of-0.215. The 19 pairs EST-SSR were analyzed in the progeny. 7 loci significantly deviated from the equilibrium.The number of alleles ranged from 2-5,average allele number was 2.316, the average values of observed heterozygosity was 0.503,the average of polymorphism information content(PIC) was 0.353, The range of Fis was between-0.405-0.303,with an average of-0.205. These results show that most of these markers will be useful for further progress of genetic breeding in turbot.For population analysis showed that the turbot breeding population, although there was a certain degree of degradation, but still relatively high level of genetic diversity can be used for further breeding. In this study, 238 markers were used to construct the genetic linkage map of turbot, which included 221 microsatellite markers and 17 EST-SSR markers. Chi-square test showed : in Female linkage maps, 37 markers significant segregation distortion(P<0.01), segregation ratio 21%; parent linkage, 35 markers significant segregation distortion(P<0.01) tags, segregation ratio of 21.2%. Finally, 136 markers linkage to the map, female map contain 94 markers, with a total length of 1099.8c M, distributed in 20 linkage groups, the average marker interval 11.7c M; male map contain 95 markers, with a total length of 1214.2c M, distributed in 22 linkage groups,the average marker interval 12.8c M. And the map has successfully positioned nine EST-SSR, and EST-SSR marker is type Ⅰ marker, which an be used to feature comparison between species and provide help for genetic screening, the map can be used to QTL mapping, and provides help for the development of molecular marker assisted breeding of turbot. |
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