Study on simulation of minimal kinship selective breeding for conservation of genetic diversity in successive artificial bred lines in fish

在鱼类制种业中，由于种子是用较小的有效育种量繁殖的，因此通常会产生近交系数高的种子群体。在本项目中，我们试图评估经济重要鱼类种群改良计划中人工繁殖种群中发生的遗传变化，以期为遗传管理寻找保护野生种群的方法：1)开发高效的遗传标记，如DNA多态性2)积累野生种群和人工繁殖种群的种群结构和多样性遗传数据3)开发一种模拟器，用于在人工制种生产中利用种群遗传数据生成后代的基因类型4)开发一种模拟器t…5)为种子生产制定指导方针，以保护种群和野生种群的遗传多样性。使用的鱼种是来自水产养殖物种、种群强化物种和濒危物种的代表性物种，如巴鳍比目鱼、湄公河巨型叉尾鲨和樱鱼。我们收集了用于种群遗传分析和模拟研究的DNA标记的基因型数据，并利用本项目开发的最小亲缘关系选择育种软件，通过30个世代的重复虚拟繁殖试验，验证了选择的最佳条件。我们发现保存遗传变异的最佳条件是等位基因平均数和在野生种群中观察到的杂合性。这种方法有助于保持每个物种的亲代群体足够的遗传分化水平，即使亲代群体的有效大小不足以小于最小可存活种群数量(Ne=50)。较少

In the fish seed production industry, seed populations with high value of inbreeding coefficient are usually produced because the seeds are reproduced using smaller effective size of brood stock. The genetic changes caused by random genetic drift, inbreeding depression, unconscious selection happened in such inbreeding population may give un-restorable effects on wild population.In this project, we tried to evaluate genetic changes happened in the artificially reproduced seed population for stock enhancement programs of economically important fish species to find up way for genetic management to conserve wild populations based on following actions :1) to develop efficient genetic markers such as DNA polymorphism2) to accumulate the genetic data of population structure and diversity of both the wild and artificially propagated populations3) to develop a simulator to generate genotypes of offspring using genetic data of brood stock in artificial seed production4) to develop a simulator t … More o perform minimal kinship selective breeding for conservation of genetic diversity in the brood stock and wild population5) to make guideline for seed production to preserve genetic diversity in the brood stock and wild populationThe fish species used were representative species from aquacultured species, stock enhanced species and endangered species, such as barfin flounder Verasper moserz; Mekong gigantic catfish Pangasianodon gigas, and sakuramasu Oncorhynchus masou. We collected genotype data of DNA markers for the population genetic analysis and simulation studies for these fishes.Using the soft wares developed in this project for minimal kinship selective breeding, the optimum conditions for selection were examined by repetitive virtual reproduction trials for 30 generations. We found the best condition to conserve the genetic variation being equivalent level of the average number of alleles, and heterozygosity observe in the wild population. This method were useful to conserve the enough level of genetic divergence of brood stock in each species, even if the effective size of brood stock are not enough being less than minimum viable size of population (Ne=50). Less