曼氏无针乌贼的多父本婚配制度及其对种群遗传变异的影响

The mating system is a basic reproductive ecological trait of animals and is crucial for animals’ recruitment and evolution. Among different types of the mating system, multiple paternity is a typical one but its effect on the animals’ evolution and ecological adaptation still remains unsolved. Multiple paternity is very common in cephalopod species, which include Sepiidae. The present study will use Sepiella japonica as the model to investigate the basic characteristics of mating system of multiple paternity in cephalopod species and its potential effect on the population genetic variation. In the study, the controlled field observation will be applied to investigate the behavioral aspects which relates to the multiple paternity mating system. Microsatellite DNA markers will be developed and used to test the basic characteristics of multiple paternity mating system. Molecular ecological method will be used to find out the mechanism which determine the frequency and other characteristics of multiple paternity. Ecological experiments will be conducted to investigate the flexibility of this multiple paternity mating system introduced to different environmental conditions. The potential impact of this mating system on the effective population size and hence the genetic variation in S.japonica population will also be evaluated by both computer simulation and by fine designed experiments. The results of this study would not only contribute to better understanding of the mating system of multiple paternity in cephalopod species and its evolutionary consequence, but also contribute to optimize the breeding scheme for captive S.japonica to prevent the inbreeding and hence the loss of genetic variation through mating system manipulation.

交配系统是物种重要的繁殖生态特征，对于维系物种繁衍和适应性进化具有重要意义。多父本婚配制度是物种典型的交配系统，但它在维持物种进化和环境适应性方面的作用一直是学术界广为关注但尚待解答的科学问题。本项目针对头足类普遍存在多父本婚配制度的特点，以曼氏无针乌贼为代表，开展其多父本婚配制度特征及对种群遗传变异影响的研究。重点采用传统行为学的方法研究乌贼多父本婚配制度的行为学基础；采用分子标记技术对乌贼多父本婚配制度及父权格局特征进行评价；利用分子生态学手段考察乌贼多父本婚配频率及父权格局的决定机制；利用生态学实验探讨多父本婚配制度的可塑性及与环境的关系。综合运用计算机模拟及实验方法评估多父本婚配制度对乌贼遗传变异的影响.本项目的研究不仅有助于对头足类多父本婚配制度及其进化生态学意义有更深入的了解，同时也为通过乌贼多父本婚配策略的调控，提高人工群体的遗传变异水平，促进其增养殖产业的健康发展奠定基础。

多父本婚配制度是物种典型的交配系统，但它在维持物种进化和环境适应性方面的作用一直是学术界广为关注但尚待解答的科学问题。本项目针对头足类普遍存在多父本婚配制度的特点，以曼氏无针乌贼为代表，开展其多父本婚配制度特征及对种群遗传变异影响的研究。重点采用传统行为学的方法研究乌贼多父本婚配制度的行为学基础，采用电镜和组织学方法分析了乌贼多父本婚配制度的组织学基础；采用分子标记技术对乌贼多父本婚配制度及父权格局特征进行评价，并阐明了乌贼多父本婚配频率及父权格局的决定机制；利用生态学实验探讨多父本婚配制度的可塑性及与环境的关系；同时利用实验方法评估多父本婚配制度对乌贼遗传变异的影响.研究结果表明，乌贼繁殖过程中存在典型的一雌多雄的交配习性，雌体口膜附着多个父本的精荚囊及纳精囊存储多个父本的精子是其多父性繁殖的组织学基础； 采用自开发的39 对多态性的微卫星引物,对人工繁育曼氏无针乌贼多父性繁殖进行鉴定，每个雌体所产子代的最小潜在父本数为3-6个，每个雄性繁殖成功存在明显的偏岐，雄性父权格局的产生与雌体口膜附着的精囊团及纳精囊中精子的父权格局有关，进一步印证了乌贼中存在着普遍的多父本繁殖策略；这种多父本繁殖策略受温度和养殖密度等环境的调节，特别是随着养殖密度的增加，多父本繁殖频率也显著增加（p<0.05），这可能与高密度养殖条件下雌体与更多雄性交配机会增多及雄性交配等级制度丧失有关。相对于单配繁殖和低频率的多父本婚配，高频率的多父本婚配可显著提高繁育群体的Ne及子代的Na、Ho、He、香浓多样性指数等遗传变异参数（p<0.05）；本项目的研究不仅有助于对头足类多父本婚配制度及其进化生态学意义有更深入的了解，同时也为通过乌贼多父本婚配策略的调控，提高人工群体的遗传变异水平，促进其增养殖产业的健康发展奠定基础。项目完成发表论文4篇，其中SCI3篇。