中华绒螯蟹微卫星标记与生长性状相关性的初步分析

摘要

Chinese mitten crab (Eriocheir sinensis), belong to order Brachyura, family Grapsiodea, is one of the most important species for aquaculture in China with an annual cultured production of about 518357 tons, especially in the Yangtze River valley. Chinese mitten crab has three main strains in China, including Yangtze River strain, Liaohe River strain and Oujiang River strain. The strain of Yangtze River exhibited excellent economical characters and is the best strain for aquaculture. However, genetic degeneration, such as low growth rate, small body size, weak disease-resistance,etc., emerged in Chinese mitten crab with the rapid development of its farming scale. Microsatellite marker is a very useful and powerful molecular marker due to its highly polymorphism, stable and co-dominance and it was widely applicated in researches of genetic diversity, kin discrimination, strain identification, genetic linkage map construction,trait-related marker screening, genetic evaluation, molecular taxonomy and so on. In this paper, Chinese mitten crabs of the Yangtze River strain were cultured in a 0.5 ha pond and 100 individuals were sampled at the same time in November.The growth traits of all individuals, including body weight, body width and body height, were measured separately. The results indicated that the growth traits were quantitative traits with the characteristic of continuous variation and complied with normal distribution according to the Kolmogorov-Smiromov normality test. Two extreme groups were chosen according to their body weight and used for primary screening of trait-related loci. The 15 individuals weighing more than 155g were selected as "maximal group" and another 15 individuals weighing less than 69 g were selected as "minimal group". Thirty microsatellite loci were used to analyse the differences between maximal and minimal groups.The results of Chi-Square test showed that 4 out of 30 loci showed significant variances of genotypes between groups.Loci ESIN33, ESC29 and ESC57 showed extremely significant difference in genotypes (P＜0.01) and locus ESC65 showed significant difference in genotypes (P＜0.05) between "maximal group" and "minimal group". The above four microsatellite loci were applied in analysis of all 100 samples. Statistical analysis showed ESIN33, ESC29 and ESC57had an extremely significant impact on body weight, body width and body height (P＜0.01) while ESC65 had an extremely significant impact on body width and height (P＜0.01) and a significant impact on body weight (P＜0.05) according to General linear model (GLM) and Duncan Correlation analysis. The results of multi-comparison of different genotypes indicated that AC at locus ESIN33, DD at locus ESC29 and BB at locus ESC65 had a positive correlation with body weight, body width and body height, and they were the most advantageous genotypes for growth traits (P＜0.05). Genotype DE at locus ESC29 had a negative correlation with body weight, body width and body height. The results also suggested that the growth traits should be determined by more than one loci which was conformed to the theory on quantitative genetics. This work investigated the correlation between microsatellite markers and growth traits in Chinese mitten crab and obtained trait-related microsatellite loci for the first time and the results would be valuable for marker-assisted breeding in Chinese mitten crab.%研究采用30个微卫星标记分析同池养殖的长江水系中华绒螯蟹群体,以筛选生长性状(体重、体长和体宽)相关的分子标记.结果表明,位点ESIN33、ESC29和ESC57与体重、体宽和体高呈极显著相关(P＜0.01);位点ESC65与体高、体宽呈极显著相关(P＜0.01),与体重呈显著相关(P＜0.05).不同基因型间的多重比较表明,ESIN33位点的AC基因型、ESC29位点的DD基因型、ESC65位点的BB基因型的平均体重、体宽和体高均高于其他基因型,且差异显著,是生长性状的优势基因型.研究结果可为中华绒螯蟹的分子标记辅助选育提供参考.