鲤杂交种对北方野生群体遗传结构干扰的研究

Common carp is one of worldwide aquaculture species, and China is the largest carp culturing and consuming country. The genetic structure of the wild population has been seriously disturbed by the escape of aquaculture species, and the degree of interference is increasing every year. Our country is the main origin of common carp, It has important scientific and economic significance for sustainable using the excellent breeding objects which accompanied by Chinese nation more than 4000 years, that clarifying the degree of wild populations affected by hybrids species, and identifying the wild populations which have not been disturbed. To elucidate the genetic structure of wild populations affected by hybrids is difficult, considering the importance and urgency of protecting the wild population. In this study, we selected north carp which individual big and strong tolerance to cold as the object. The specific SNP of European carp, which was one of the hybrids of hybrid carp, was indicated as the indicator, and the sequencing data of common carp as genome reference. Exploring whether or not the wild population is affected by genetic interference by the new technology of germplasm identification based on the established population genomics, and in combination with the SNP markers tightly linked scale cover pattern, body color and morphology traits to investigate the hybrids cause wild populations allele "super invasion" phenomenon. To get exact conclusion on the interference degree of hybrid wild population genetic, also hope to identify wild populations of remote lakes without interference of the proposed hybrid carp, germplasm conservation measures and suggestions.

鲤是世界性的水产养殖种之一，我国是最大的鲤养殖国和消费国。养殖逃逸等使野生群体的遗传结构受到了严重干扰，而且干扰程度每年都在加剧。我国是鲤的主要起源地，阐明野生群体受杂交种的干扰程度，鉴定出未受干扰的野生群体，对持续利用这个伴随中华民族4000多年的优秀养殖对象具有重要的科学和经济意义。针对阐明杂交种对野生群体遗传干扰的技术难度大的问题，考虑到保护野生群体的重要性和紧迫性，本研究以个体大、耐寒力强的北方鲤为对象，以杂交鲤种源之一的欧洲鲤特异SNP为指示标记，以鲤全基因组测序资源为参考，利用已建立的群体基因组学的种质鉴定新技术，探索野生群体是否受到杂交种的遗传干扰，并结合鳞被、体色和形态等性状紧密连锁的SNP标记，调查杂交种对野生群体等位基因的“超入侵”现象，最终获得杂交种对野生群体遗传干扰程度的确切结论，同时希望鉴定到偏远湖泊未受杂交鲤干扰的野生群体，提出种质保护措施和建议。

本研究为了评估杂交种对野生群体的遗传干扰程度，以个体大、耐寒力强的北方鲤为对象，(1)用线粒体基因序列分析了鲤杂交种、北方野生群体及主要养殖种的遗传变异，共检测34个COI单倍型，松浦镜鲤的5个单倍型在野生群体中检测到，松浦镜鲤对野生群体的遗传干扰较大；共检测到22个COII单倍型，中国野生鲤种群的遗传多样性水平高于引进的欧洲鲤品系及中国地方品种，海南鲤群体最先与其他鲤群体分离，海南鲤与其他欧亚鲤群体的显著分离支持鲤起源于东亚的假说。(2)用微卫星分析了鲤野生群体与养殖群体间的遗传结构及遗传分化，结果鲤野生群体的遗传多样性高于养殖群体，鲤群体间分化显著，野生群体多受养殖的遗传污染，茂兴湖、佳木斯原种场和西泉眼水库受到镜鲤基因污染，东平湖受到黄河鲤基因污染。(3)对19个主要鲤种群开展了基于基因组重测序的遗传结构分析，结果显示：黑龙江流域一些鲤群体含有欧洲、日本锦鲤、荷包红鲤以及黑龙江鲤祖先遗传成分，可能是因为人工养殖群体逃逸后导致的遗传渗透或是祖先群体的多样性过高；黑龙江抚远群体基本上保留着完整的黑龙江鲤祖先遗传成分，并未受欧洲和其它祖先遗传成分的干扰；松浦镜鲤(SP)所含的欧洲鲤组分对黑龙江流域的野生群体有一定程度的遗传渗透，对西泉眼水库、佳木斯原种场和月亮湖等3个群体的影响较大，呼伦湖、黑龙江和乌苏里江抚远江段未受松浦镜鲤的遗传干扰。研究结果从线粒体基因序列、核基因标记及基因组重测序3个层面分析了杂交种对北方鲤野生群体的遗传结构干扰，摸清了野生鲤群体受杂交种干扰的情况，鉴定出未受干扰的野生群体，对鲤种群的持续利用具有重要的科学和经济意义。