The Screening Of Growth-related Microsatellite And Parentage Assignment In Cirrhinus Molitorella

The mud carp(Cirrhina molitorella) is primarily distributed along the south of China and Southeast Asia. In the Pearl River Basin, the mud carp is considered as one of the four major Chinese carps, along with grass carp, sliver carp and bighead carp in South China, and mud carp is used as a significant farming and fishing species native to South China. To make clear the genetic structure of wild populations for the mud carp, provide some capable measures for the protection of genetic resources, develop more breeding source for the artificial selection, we make a assessment about the genetic diversity of the mud carp spreading over the Zhaoqing, Xijiang; Seven microsatellite loci which indicate their significant or highly significant association with growth traits have been achieved when analyzing the association between them and growth characteristics, and finally the advantage genotype were screened successfully; The paternity analysize has been conducted base on the establishment of a multiplex genotyping system, which will provide a new breeding techniques for the mud carp. The detailed content is as follows:1. Twelve pairs of novel primers based on the transcriptome of the mud carp was developed and characterized for genetic polymorphism analysis in 64 wild individuals in our laboratory. The microsatellite loci exhibited a range of alleles of 3 < K < 7 with an average of 4.25. The observed heterozygosity ranged from 0.375 to 0.7656 with an average of 0.6198. The expected heterozygosity ranged from 0.3863 to 0.7714 with an average of 0.6322. The average Polymorphism Information Contentthe was 0.574. Ten loci were in the HWE,while two loci deviated significantly from the HWE. These novel microsatellite markers will be valuable for population genetic analysis and sustainable fishery management and conservation of genetic resources for the mud carp and related species.2. Fifty candidate microsatellite loci were applied in association analysis between them and the growth traits for dace with the Least Square Method by the General linear models, The results indicated that three microsatellite loci ZJ35108、HLJ6 and ZJ33806 had extremely significant correlation with body weight, body length and overall length, while MFW1 had extremely significant correlation with body weight and significant correlation with body length and overall length, ZJ15254 and ZJ34676 had significant correlation with body weight, body length and overall length, ZJ12551 had merely significant correlation with body weight, but no correlation with body length and overall length. Finally, multiple comparisons were carried out between growth characters and different genotypes in the same locus, which had significant correlation with the growth traits by using Duncan method, and initially acquired 7 valuable microsatellite markers and 3 genotypes involved in the individuals that have advantages in growth, which provided a new technological means for the genetic improvement and selective breeding for dace.3. In this study, the multiplex PCR system consist of thirteen pairs of primers screened from the developed microsatellite markers based on the data of mud carp from our laboratory, and by adjusting the primers ratio, the number of cycles and the time of extension to achieve a stable and clarity purpose bands, base on which, the genetic analysis and parentage assignment were carried out of 2 male, 5 female and 146 descendish of them. The result draw the number of alleles 2 <K <5, with an average of 3.54; The polymorphism information content ranges from 0.271 to 0.697, with an average of 0.4953; And the observed heterozygosis ranges of 0.183 ~ 0.778, mean observed heterozygosis was 0.6008; The expected heterozygosis ranges from 0.324 to 0.741, the average expected heterozygosis was 0.5572; The null allele frequency was 1.29% ~ 27.68%; The success rate of the simulation and actual identification was 99% and 100% for offspring, respectively, which provide a new technological means for the study of selective breeding and genetic resources for dace.