| The large-scale loach Paramisgurnus dabryanus is a little common economic fish. It has become an important object of aquaculture with rich nutrition. The author established families of large-scale loach, screened the families which have advantage of growth and further excavated the SSRs which associate growth trait and analyzed the genetic structure of five families of Paramisgurnus dabryanus. This study laid the foundation for obtaining Paramisgurnus dabryanus stain with rapid growth, genetic stability and high quality.1 Exploring growth-associated SSRs of Paramisgurnus dabryanusTwenty eight growth-associated SSRs were used to do growth correlation analysis in 60 large-scale loaches which were from a mass selection group. In order to verify the relevance between growth and SSRs, we made searching in non-redundant protein database of NCBI by Blastx, and found the homologous proteins of transcript sequence. The general linear model in the spss20.0 software was used to analyze the correlation between growth and growth trait(body length, total length, body height, body weight and shell weight) with the least significant difference(LSD). The results showed that among 28 SSRs, 11 SSRs were significantly associated with growth;and a lot of dominant genotypes of growth traits were found; 10 of 11 SSRs that their transcript sequence had been found homologous proteins in the NR protein database, except the SSR Pda247; 7 of 11 transcript sequence were similar to zebrafish, and most of the homology was above 90%; The homologous protein were related to the metabolism of the fish, and participate in the process of fish growth and development.2 Screening fast-growing families of Paramisgurnus dabryanus and analysis of the effect of genotypes on growth.Eleven families of large-scale loach were established in this experiment, and fast-growing families were screened by comparing growth traits between the families, and growth-associated SSRs were used to analyze the effect of genotype on growth by genotyping. One way ANOVA had been used to compare growth traits(body length, total length and body height). The results by multiple comparisons showed that, the mean value of body length, total length and body height of AB2013F-7 was significantly greater than other families(P<0.05); each growth trait of AB2013F-89 and AB2013F-45 was significantly greater than some other families; during the 117 days of cultivation, the three families with the highest daily weight gain were AB2013F-7, AB2013F-89 and AB2013F-45(0.06834 g/d, 0.05095g/d and 0.04754g/d respectively). The result of genotyping of 11 pairs of parents showed that the growth rate of each family in accord with the number of growth associated SSR. The number of dominant genotypes of each families and the mean of growth trait was positive correlation. The more dominant genotype the family had, the faster the growth rate of the family.3 Genetic structure analysis in five families of Paramisgurnus dabryanusTo provide technical parameters for breeding of Paramisgurnus dabryanus, 20 microsatellite markers were applied to analysis of the genetic structure of five families. Results showed that a total of 53 alleles were detected in five families of P. dabryanus for 20 simple sequence repeats(SSRs), the mean number of alleles was 2.65, the number of alleles ranged from 2 to 4 for each loci; the average observed heterozygosity(Ho) ranged from 0.3117 to 0.5542 in five families; the average expected heterozygosity(He) ranged from 0.3261 to 0.4371; the average polymorphic information content(PIC) ranged from 0.3459 to 0.4538; the average fixed coefficient(Fis) was-0.0472(<0) and the genetic differentiation coefficient(Fst) was 0.2703 in five families; UPGMA cluster analysis showed the families kinship of AB2013F-7 and AB2013F-81 was the farthest. Studies suggested that five P. dabryanus families had large genetic differentiation and large breeding potential. |
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