广东沿海3个斜带石斑鱼养殖群体的RAPD和线粒体Cytb基因序列变异分析

摘要

Epinephelus coioides is an important mariculture commercial fish in South China. In recent years,due to excessive fishing and rapid expansion of artificial breeding,the natural resources of E. coioides have declined and their genetic diversity has decreased. We applied random amplified polymorphic DNA(RAPD)and mitochondrial cytochrome b(Cyt b)gene sequences analyzing technique to three cultured stocks of E. coioides sampled from Huizhou,Shenzhen and Zhanjiang. The main results show that:1)RAPD analysis might be more sensitive than mitochondrial Cyt b gene sequence to reveal genetic variations of E. coioides;2)Compared with the other reported groupers,the genetic diversity of E. coioides might be affected by overfishing and aquaculture. The percentage of polymorphic loci was 40. 57% according to RAPD analysis;3)The genetic identity was 0. 967 1 ~ 0. 980 8 according to RAPD analysis and the nu-cleotide diversity of Cyt b was only 0. 003 8. Small differentiation and similar genetic background were observed among E. coioides stocks. Furthermore,we explored the characteristics of mitochondrial Cyt b of E. coioides and put forward some suggestions and coun-termeasures for protecting genetic diversity of E. coioides.%斜带石斑鱼（Epinephelus coioides）为中国南方重要的海水增养殖经济鱼类，但过度捕捞和人工养殖的快速扩张导致了其自然资源衰退和遗传多样性降低。文章采用随机扩增多态 DNA（RAPD）和线粒体细胞色素 b（Cyt b）基因序列分析方法，对惠州、深圳和湛江3个斜带石斑鱼养殖群体进行了遗传多样性状况和遗传差异的研究。结果表明：1）相比较于线粒体 Cyt b 基因序列分析，RAPD 技术在研究斜带石斑鱼种内遗传变异方面具有更高的灵敏性和多态性；2）相比较于其他已经报道的石斑鱼类，斜带石斑鱼的遗传多样性较低，RAPD 检测到的多态位点百分率（P）为40.57%，究其原因，可能是受过度捕捞和人工养殖的影响；3）RAPD 检测到的群体间遗传相似度（I）高达0.9671~0.9808，而 Cyt b 的核苷酸多样性仅为0.0038；斜带石斑鱼养殖群体间的遗传差异显然很小，具有相似的遗传背景。文章还探讨了斜带石斑鱼线粒体 Cyt b 基因的特点，并针对目前斜带石斑鱼的养殖现状提出了相应保护遗传多样性的对策与建议。