作　　者： (宋素霞）; (丁少雄）; (鄢庆枇）; (覃映雪）;

机构地区： 集美大学水产学院、农业部东海海水健康养殖重点实验室,福建厦门361021

出　　处： 《水产学报》 2017年第8期1183-1191,共9页

摘　　要： 为科学保护和开发我国光裸方格星虫自然资源,本研究以cytb基因全长为分子标记分析了山东烟台、福建古雷、香港、海南儋州、海南陵水、广西东兴6个光裸方格星虫群体的遗传多样性。结果显示,203个个体共检出128个单倍型,299个多态位点,核苷酸多样性和单倍型多样性分别为0.0488和0.9773,且变异主要来自群体间(88.4%)。6个光裸方格星虫群体间遗传分化指数(F_(st))分析结果显示,南方5个群体间F_(st)<0.15,基本无分化或呈低度分化;而烟台与南方5个群体间的固定指数都很大,F_(st)>0.15,群体间呈高度分化。中性检验(Fu’s Fs、Tajima’s D)结果为负值,北方群体和南方群体的核苷酸错配分布图为单峰,单倍型网络分布图为以主单倍型为中心的放射状结构。用203条cytb序列构建的系统发育树显示,烟台群体聚为一个进化支,南方群体聚为一个进化支。研究表明,中国沿海的光裸方格星虫群体在历史上经历过大规模群体扩张,但目前遗传多样性较低,说明光裸方格星虫对环境变化的适应能力较差,应加强野生资源的保护,在进化关系上,烟台群体与其他5个群体之间存在较大的遗传分化,但是否已经形成隐秘种仍需进一步的研究。 Sipunculus nudus resources have been seriously damaged in the recent years due to overfishing and habitat destruction. Protecting natural resources of S. nudus has become more and more urgent. In this paper,genetic structure and population differentiation of S. nudus from 6 localities along the coasts of China were analyzed based on sequences of mitochondrial cytochrome b gene. Complete mitochondrial cytb sequences from 203 individuals of S. nudus were analyzed, 299 polymorphic sites and 128 haplotypes were identified and the nucleotide diversity and haplotypes diversity were 0.0488 and 0.9773, respectively. The variation among populations（accounting for 88.4%） was the main source of variation. According to differentiation index（Fst） in populations of S. nudus, the 5 populations in the south of Yantai showed no significant differences or low differences, with Fst0.15. There were high differences between Yantai and other 5 populations, with Fst0.15.Fu＇s Fs and Tajima＇s D were negative. Figures of mismatch distribution were unimodal. Haplotype network was radial structure centering on main haplotype. NJ phylogenetic tree of S. nudus based on 203 sequences of cytb of mt DNA revealed that these 6 populations were divided into 2 clades, one clade was Yantai population and the other clade included the rest 5 populations in the south of Yantai. All these results revealed that S. nudus population had experienced a large-scale population expansion in history, and the relatively low genetic diversity of S. nudus now suggested that the ability of S. nudus to adapt to environmental changes was poor and some measures should be taken to protect S. nudus resources. Phylogenetic tree suggested Yantai population was distinct from the other 5 populations, but whether Yantai population has become a cryptic species still needs further research.

关 键 词： 光裸方格星虫 遗传多样性 群体结构 系统发育