基于cSNP的合浦珠母贝生长性状非加性遗传效应的剖分

Oyster is a cold-blooded invertebrate. Genetic effects and environmental factors, which ones have greater effects on its growth is reamin unknown. Genetic effects include additive effect and non-additive effects (dominance and epistasis). In the current breeding program research, additive effect estimate was studied much more than non-additive effect. Studies showed that heritabilities are relatively low but hybrid vigors are high in most oysters, suggesting that additive effects are small but non-additive effect are big. Thus accurate estimation of non-additive effects is crucial to understand the extent of genetic effect on the growth. Therefore, precisely making clear the composition of the genetic effects is the requisite of accurate estimate of breeding value and related to breeding strategy making and accuracy of selection. Hence in this study, we plan to make genetic combinations according to nest,factorial and diallele mating designs using selected family and population lines as broodstock, and put them in Hainan, Guangdong and Guangxi farms for culture. Growth and cDNA SNP data will be collected. The size and components of genetic effects will be clarified through the estimation of additive, dominance and epistatic effects using pedigree based BLUP and SNP genotype based GBLUP, plus GWAS of epistatic effect as well. By doing so, the breeding value will becaculated, based on which new breeding strategy will be made accordingly and used to breed next generation for validation.With the complete of this study it is expected to provide scientific basis for genetic improvement of the pearl oyster Pinctada fucata.

贝类属于低等变温无脊椎动物，遗传效应和环境因素两者对其生长的影响谁大谁小尚缺乏研究。遗传效应包括加性效应和非加性（显性与上位性）效应。目前育种研究中对加性效应的研究较多，而非加性效应的研究少。研究表明，贝类遗传力较低（0.2左右）而杂交优势较高，意味着加性效应小而非加性效应大。因此非加性效应的准确估计是弄清贝类遗传效应大小的关键，而遗传效应构成的精确剖分，是准确估计育种值的前提，直接涉及到育种策略的制订和育种选择的准确性。因此本项目拟利用合浦珠母贝家系和群体选育材料作亲本，依据巢式、因式和双列杂交等交配方案构建遗传组合，于海南、广东、广西不同地点养殖，采集生长数据和cSNP基因型数据，用基于系谱信息的BLUP和基于SNP基因型信息的GBLUP进行加性、显性和上位性遗传效应剖分及上位效应的GWAS分析，精确估计遗传效应大小及其构成，并制订育种策略进行验证，为合浦珠母贝遗传改良提供科学依据。

项目通过利用合浦珠母贝群体和家系育种材料作为亲本，先后构建了190个巢式设计交配家系、17个双列杂交群体和30个因式交配设计家系，并进行了多地点养殖性能测试和保种留种工作，开发了合浦珠母贝性状测量、整理和育种管理等3个软件，共计收集了740292条性状数据，并利用个体系谱亲缘关系和SNP信息，估计了生长性状的加性效应和非加性效应等遗传参数，发现存在非加性遗传效应，提出了BLUP+杂交的育种策略，优化了生长性状遗传改良方案。项目执行期间共发表学术论文21篇，其中SCI 5篇，申请发明专利1项，授权实用新型专利10项，培养2名硕士研究生和1名博士研究生，获得合浦珠母贝“南珍1号”新品种1个，相关成果分别获得国家海洋局海洋科学技术二等奖（合浦珠母贝良种选育技术，2016年度）和神农中华农业科技奖二等奖（合浦珠母贝新品种选育与应用，2017年度）。