三角帆蚌HcTyr基因内壳色性状相关SNP筛选及图谱定位

Detection of shell nacre colour-related SNP and gene mapping of HcTyr gene in Hyriopsis cumingii

为研究三角帆蚌HcTyr基因与内壳色性状的相关性,本实验根据已分离的三角帆蚌HcTyr基因进行引物设计和片段扩增,并用144只三角帆蚌对其多态性进行筛选和验证,卡方检验分析了SNP位点和三角帆蚌内壳色相关性,并对HcTyr基因进行了图谱定位。结果显示,在HcTyr基因上筛选出8个SNP位点,其中有7个SNP位点与三角帆蚌内壳色L、a及d E呈显著相关性,用这7个SNP位点做单倍型构建和分析,发现Ⅱ、Ⅲ及Ⅳ这3种单倍型在白色群体中出现的频率极显著高于在紫色群体中出现的频率,而Ⅴ和Ⅶ这2两种单倍型在紫色群体中出现的频率极显著高于白色群体。进一步在商业养殖群体中验证发现,Ⅳ和Ⅶ这2种单倍型可分别作为白色和紫色群体的优势单倍型。研究表明,三角帆蚌HcTyr基因可作为内壳色相关的候选基因,其部分SNP位点可用于三角帆蚌分子辅助育种。另外本实验还将HcTyr基因定位在三角帆蚌LG16连锁群上,这为进一步解析该基因调控珍珠颜色形成的分子机制奠定了基础。

In order to study the correlation between HcTyr gene and shell nacre colour, genomic sequence fragments were amplified according to cDNA fragments of HcTyr gene. Regarding the detected SNP, the genotype and the polymorphic information（PIC） of 144 Hyriopsis cumingii were analyzed, and the correlation between SNP and shell nacre colour-related traits were further analyzed using Chi-square test. Moreover, the location of HcTyr gene on gene map was also studied. The results showed that 7 of the 8 detected SNP in HcTyr gene were significantly associated with shell nacre colour（L, a and d E）. Haplotype analysis revealed that the frequency of three major predominant haplotypes（Ⅱ, Ⅲ, Ⅳ） in the white strain was significantly higher than that in the purple strain. And the other two major predominant haplotypes（Ⅴ and Ⅶ） showed significantly higher frequency in the purple strain. The haplotypes were further validated in commercial cultured populations and the results showed that Ⅳ and Ⅶ can be considered as predominant haplotypes for white strain and purple strain respectively. The results suggest that HcTyr could be candidate shell nacre colour related genes for H. cumingii, and some polymorphic loci in this gene could be potential genetic markers for molecular breeding. Furthermore, we mapped HcTyr gene on LG16 of the previous linkage map, which will lay the foundation for the further study of the molecular mechanisms about this gene.