三疣梭子蟹生长相关 SNP 位点的鉴定 [中文引用][英文引用]

<p>&nbsp;&nbsp;为了发掘三疣梭子蟹(Portunus trituberculatus)与生长相关的SNP, 本研究基于三疣梭子蟹比较转录组学数据, 筛选出生长相关候选基因片段19条, 利用该基因序列设计引物进行PCR扩增, 得到总长为17 387 bp的DNA片段; 通过直接测序法发现 74 个 SNP 位点, 分布频率为 0.43/100 bp, 其中转换突变的比例为 80%, 颠换突变的比例为 20%, 转换的比例远远大于颠换, 符合&ldquo;transition bias&rdquo;原理。C/T(G/A)突变所占比例为 60%, G/T(C/A)突变占 20%, A/T 突变占 9.33%, G/C突变占 10.67%, C/T(G/A)突变所占比例最大。内含子上突变发生的频率为 1.34/100 bp, 外显子 上仅为 0.17/100 bp, 说明外显子上的碱基更加保守。通过飞行质谱法, 在三疣梭子蟹生长性状分离群体中成功分型 了 10 个 SNP 位点; 通过卡方检验和多元方差分析的方法进行性状关联分析, 发现 3 个 SNP 位点与生长性状显著 相关(P&lt;0.05), 并且 comp58070-R31 位点与生长性状极显著相关(P&lt;0.01); 一般线性模型的多元方差分析显示, comp58070-R31位点与体重、全甲宽、甲宽3个性状极显著相关(P&lt;0.01), 与体长、体高2个性状为显著相关(P&lt;0.05); comp46623-F49 位点与甲宽显著相关(P=0.05); comp49193-R333 位点与甲宽显著相关(P&lt;0.05)。通过对 SNP 位点的 多态性分析发现, 三疣梭子蟹 SNP 标记观测杂合度(Ho)范围为 0.162 8~0.833 3, 期望杂合度(He)范围为 0.189 6~ 0.591 2, 并且显示 SNP 标记的信息量低于微卫星标记。该研究的结果将有助于推进三疣梭子蟹分子标记辅助育种 进程。&nbsp;</p>

<p>Comparative transcriptomics data have become one of the most important ways to study single nucleotide<br /> polymorphisms (SNP). We have identified 129 gene segments associated with growth. SNP is a third-generation molecular<br /> marker and is useful for breeding rapidly growing species, such as the swimming crab, Portunus trituberculatus.<br /> We developed an efficient method to selectSNPs correlated with P. trituberculatus growth. Time-of-flight-mass spectrometry<br /> was used for SNP typing, and the chi-square test was used for the correlation analysis. Nineteen gene segments<br /> were amplified based on comparative transcriptomics, and a total of 17 387 bp DNA fragments were amplified. SNP<br /> frequency was estimated to be 0.43/100 bp of DNA sequence, the conversion mutation rate was 80%, and the transversion<br /> mutation rate was 20%. The conversion ratio was far greater than the transversion ratio to comply with the principle<br /> of &ldquo;transition bias&rdquo;. The G/T (C/A) rate was 20%, the A/T rate was 9.33%, the G/C rate was 10.67%, and the C/T<br /> (G/A), which is the most common gene mutation type, was 60%. The intron mutation frequency was 1.34/100 bp and<br /> that of exons was 0.17/100 bp, indicating that the exon mutation frequency was more conserved. Three SNP markers<br /> were significantly correlated with growth traits, and P-values of 10 SNPs were &lt; 0.05. The chi-square test result revealed<br /> that comp58070-R31 was closely related to growth traits (P&lt;0.01). A multivariate analysis of variance showed<br /> that comp58070-R31 was closely related to body weight, full carapace width, and carapace width (P&lt;0.01). A significant<br /> correlation was detected between body length and body height(P&lt;0.01). Loci comp46623-F49 and comp49193-R333<br /> were significantly correlated with carapace width (P&le;0.05). Observed heterozygosity of the P. trituberculatus SNPs<br /> was 0.162 8&ndash;0.833 3, and expected heterozygosity was 0.189 6&ndash;0.591 2, indicating less information content than that<br /> from microsatellite markers. These SNPs will be helpful for pedigree analysis, association studies, and<br /> marker-associated selection in this crab species.</p>