鳜(Siniperca chuatsi)、大眼鳜(Siniperca kneri)、斑鳜(Siniperca schezeri)为鳜属中3种主要经济鱼类,具有较近的亲缘关系和相似的生活习性,但生长性状差异较大。为探索3种鳜鱼生长差异与基因差异间联系,以野生群体为材料,采用PCR扩增、电泳及测序等方法,对生长发育相关基因生长激素(GH)基因进行了多态性检测与分析。在第一内含子、第二内含子前段、第二内含子中段微卫星序列及第三内含子中均检测到多态性。各区域共检测到25种长度类型,其中4种为鳜与大眼鳜共有长度类型,3种为鳜、大眼鳜与斑鳜共有长度类型,其余18种为各物种特有长度类型。各区域长度类型共组成14种单倍型,无种间共有单倍型。序列长度差异主要由重复序列及DNA片段的插入或缺失形成。在第1内含子3’端-6位与第3内含子5’端+16位各发现一处靠近剪接位点的序列差异。根据多态性检测结果构建系统发育树,鳜与大眼鳜先聚为一枝。本研究可为进一步确认鳜鱼GH基因差异与生长性状间联系,并利用基因差异进行鳜鱼种质资源保护及分子育种奠定基础。
Siniperca chuatsi, S. kneri, S. schezeri are three major commercial fish species in genus Siniperca; they have close relationships and similar life habits, but significantly different growth. To understand the reason, the diversity of GH genes of three members is studied using PCR amplification, electrophoresis, and sequencing. Sequence diversities were observed in Intron 1, forepart of Intron 2, and microsatellite sites in Intron 2 and Intron 3. Twenty-five length types have been observed in all regions, among them 4 types are shared by S. chuatsi and S. kneri, and 3 types shared by three fishes; others were species-specific. All the length types in different regions formed 14 haplotypes, being species-specific. The sequence diversities are mainly due to repeat sequences and inserts or deletions of DNA fragments. There were two diversity loci close to the 3'-acceptor splice site of Intron 1 and the 5'-donor splice site of Intron 3 respectively. Phylogenetic tree was constructed based on diversity detections. S. chuatsi and S. kneri cluster into one clade before join S. schezeri. All these findings have laid a foundation for further study on the relationship between gene diversity and trait difference, as well as for further utilization of the diversity of GH gene in molecular breeding and germplasm conservation of the Siniperca fishes.