【摘要】 通过AFLP技术对中国东南沿海的3个不同体色花尾胡椒鲷(Plectorhinchus cinctus)养殖群体进行了遗传分析。6对引物组合从3个群体中扩增出370个位点,其中多态位点比例为49.5%,每对引物组合扩增的片段为51~71条,平均61.3条,每对引物组合多态位点检出率为39.4%~56.5%。正常群体、白色和灰色变异群体的多态位点比例分别为41.4%、36.3%、34.3%,平均杂合度分别为0.1145、0.0887和0.0837。遗传多样性衡量指标表明,正常花尾胡椒鲷养殖群体的遗传变异量相对最大,遗传多样性相对较高,白色变异群体次之,而灰色变异群体最低,白色变异群体和灰色变异群体两者间遗传多样性差异并不显著(P>0.05),显示变异群体的遗传多样性降低。正常群体与白色群体之间的遗传距离(0.0354)最大,遗传相似系数最小(0.9652)。同时,遗传分化系数Fst(0.1362)和AMOVA方差分量百分比(10.68%)也表明群体间存在着一定程度的遗传结构分化,说明对体色这一特定表型性状的人为定向选育对花尾胡椒鲷养殖群体的遗传变异产生一定的影响。更多还原

【Abstract】 Yellow-spotted grunt Plectorhinchus cinctus is a commercially important marine fish cultured in both southeast coast and Taiwan Province of China. At present,the technology on mass seed production and grow-out in a large scale are well established for this species in these areas. During the period of artificial breeding,the stock of morphs with white body and black eyes appeared in normal stock first,and then grey-morph stock differentiated from white stock. In order to assess genetic variation in these different Plectorhinchus cinctus stocks with different body color,to investigate their genetic structure,to evaluate the impact of artificial breeding on their genetic diversity and provide a baseline for further study of genetic breeding and population evolution as well,a total of 90 yellow-spotted grunt were collected from three different localities in both Fujian and Guangdong Provinces in 2004. Among them,12 randomly sampled fish from each stock were used for genomic DNA isolation,and then the amplified fragment length polymorphic (AFLP) technique was employed to analyze genomic DNA polymorphism. The results showed that a total of 370 DNA amplification bands ranging from 100 to 900 bp were produced using 6 pairs of primer combinations selected for the three stocks,including EcoRI-ACC/MseI-CAG,EcoRI-ACC/MseI-CTC,EcoRI-ACC/MseI-CAC,EcoRI-ACT/MseI-CTC,EcoRI-AAC/MseI-CAT and EcoRI-AAC/MseI-CAC,of which 183 were polymorphic and the proportion of polymorphic loci was 49.5%. The amplified bands ranged from 51 to 57 with an average of 61.3 for each primer combination,and the detecting rate of each primer varied from 39.4% to 56.5%. These 6 primer combinations yielded 353 bands,317 bands and 327 bands,respectively,with 146,115 and 112 polymorphic loci for normal,white morph and grey morph stocks. Percent polymorphic loci of 41.4%,36.3% and 34.3% and average heterozygosity of 0.114 5,0.088 7 and 0.083 7 were determined in normal stock,white morph stock and grey morph stock respectively,which clearly showed the trend in the reduction of genetic diversity in morph stocks in comparisons with normal stock. The maximum genetic distance(0.035 4)was also detected between normal and white morph stocks with minimum genetic coefficient(0.965 2). At the same time,genetic division coefficient Fst(0.136 2)and percent variance component of AMOVA(10.68%)also indicated that some genetic differentiation occurred in these three stocks. There existed a certain genetic structure differenciation among them,but there was still more genetic divergence within the stocks than that between the stocks. Either NJ cluster analysis or UPGMA cluster analysis classified normal stock and grey stock into the same category,and white stock was another cluster. It is concluded that genetic divergence is higher in normal stock than that in white or grey stock;the former has rich genetic diversity and grey stock possesses low genetic divergence and diversity compared with the two others. Selective breeding in terms of body color as a specifically phenotypic trait has some impacts on genetic variation of farmed stocks of P. cinctus. However,due to a comparatively short time of isolation in each stock,there has been no significant genetic difference between them so far(P>0.05).更多还原