半滑舌鳎有效群体大小估计

为了解半滑舌鳎当前的群体遗传结构，探究半滑舌鳎有效群体大小(N_e)发展趋势及现状，实验通过性别特异性分子标记随机鉴定了800尾半滑舌鳎的遗传性别，选取297个遗传雌性半滑舌鳎样本进行简化基因组测序(2b-RAD)，获得了64 416个可用SNP标记，利用这些标记进行全基因组范围的连锁不平衡分析得到各染色体上连锁不平衡分布；根据标记间不同物理间距进行半滑舌鳎有效群体大小的估计，初步了解各历史世代下有效群体规模；通过选择0.1、0.2、0.5、1.0、2.0、5.0、10.0 Mb等7个不同染色体片段大小反映出半滑舌鳎群体遗传结构经过自然与人工共同选择的历史发展趋势。结果显示，半滑舌鳎有效群体大小随其连锁不平衡程度衰减而呈连续下降趋势，至2世代前其有效群体大小仅为29尾左右。

Effective population size estimation of half-smooth tongue sole(Cynoglossus semilaevis)

To understand the current population genetic structure of half-smooth tongue sole and explore the trend and status of effective population size (N_e) in half-smooth tongue sole, in this paper, 800 4-month-old half-smooth tongue sole were identified by gender-specific genetic markers, and 297 genetic females were selected. Then64 416 SNP markers were obtained by simplified genome sequencing method (2b-RAD). The genome-wide linkage disequilibrium (LD) was used to obtain the linkage disequilibrium distribution on each chromosome. The effective population size was calculated based on the different physical distances between the markers for each historical generation. In order to analyze the genetic structure of the population of half-smooth tongue sole selected by natural and artificial means, the sizes of 7 different chromosomal fragment lengths were detected. And the results showed that the effective population size two generations ago was only about 29. The high-throughput 2b-RAD sequencing method was first applied to the estimation of the effective population size of aquatic animals, which provided a reference for the breeding work of other aquatic species. The effective population sizes decreased when the historical generation was closer. It is important for half-smooth tongue sole breeding and conservation to estimate the effective population size for current generation.