小黄鱼♀与大黄鱼♂杂交子代及其双亲IGF-1基因的表达差异分析

IGF-1 Expression Analysis of Larimichthys polyactis♀×L.crocea♂and Its Parents

为了研究IGF-1基因在小黄鱼、大黄鱼及其杂交F1代个体中的表达量差异,设计同一引物并利用qRT-PCR技术测定了15月龄3种鱼雌雄个体肌肉、肝脏和脑中IGF-1基因的表达量。对利用荧光定量引物PCR扩增的产物序列进行序列比对和氨基酸序列分析发现,大黄鱼和小黄鱼的扩增产物序列完全一致,杂交F1的扩增产物与双亲的相似性为96.29%,说明大黄鱼和小黄鱼杂交后代出现了一定的遗传变异,这可能与杂种优势的形成有关。IGF-1基因表达量分析得知,15月龄的3种鱼体内3种组织表达量从高到低排序均为:肝脏>脑>肌肉,并且雌性个体中该基因的表达量普遍高于雄性。此外,IGF-1基因在3种鱼同一组织的表达量差异显著:肝脏和脑中IGF-1基因的表达量从高到低依次为小黄鱼>杂交F1代>大黄鱼;3种鱼雌性个体肌肉的表达量从高到低依次为:小黄鱼>杂交子代>大黄鱼,雄性个体肌肉的表达量从高到低依次为:小黄鱼>大黄鱼>杂交F1代。比较发现,3种鱼3个组织中的IGF-1基因表达量的排序结果与体质量的排序结果相反(除了大黄鱼肌肉中IGF-1的mRNA表达),说明基因与性状并不是一一对应关系,还收到其他因素的影响。上述研究结果对于解析杂交子代的杂种优势形成机理具有重要意义。

In order to study the difference of IGF-1 gene expression in Larimichthyspolyactis,L.crocea and their hybrid(L.polyactis♀×L.crocea♂),the level of IGF-1 gene expression in muscle,liver and brain of 15 months old male and female of the three kinds of fish were determined by qRT-PCR.Sequence alignment and amino acid sequence analysis of the amplified product sequences revealed that the amplified product sequences of L.polyactisand L.crocea were completely identical.The similarity between the amplified product of hybrid and the parents was 96.29%,indicating that the certain genetic variation has occurred in the hybrids crossed by the L.polyactis and L.crocea,which may be related to the heterosis of the hybrids.According to the analysis of IGF-1 gene expression,the expression levels of the three tissues in the three kinds of 15 months old fish were:liver>brain>muscle,and the expression level of the gene in female individuals was generally higher than that in males.In addition,the expression levels of IGF-1 gene in the same tissue of three fish species were also significantly different.For the three fish,the order of the IGF-1 gene expression levels in liver and brain from high to low was L.polyactis>hybrids>L.crocea.The gene expression in muscle of the three kinds of female fish was:L.polyactis>hybrid>L.crocea,but the gene expression in muscles of the three kinds of male fish is L.polyactis>L.crocea>hybrids.It was found that the ranking results of IGF-1 gene expression in the three tissues of the three fish were opposite to those of the body mass(except for the expression of IGF-1 mRNA in the muscle of L.crocea),indicating that the genes and traits are not one-to-one correspondence.Which is also received the influence of other factors.The above research results are of great significance for the analysis of the heterosis formation mechanism of hybrids.