摘要
比较分析了棘头梅童鱼(Collichthys lucidus)和黑鳃梅童鱼(C.niveatus)的16SrRNA和Cytb基因片段序列差异及遗传分化程度。在长度为526bp的16S rRNA和379bp的Cytb基因片段的核苷酸序列中,2种间共检测到44处核苷酸替代。分析结果表明,2个基因片段的鸟嘌呤(G)含量较低,在Cytb蛋白质编码基因第三密码子位点上表现尤为明显。基于16S rRNA和Cytb基因片段分析结果显示,2种间平均遗传距离分别为0.012和0.111。构建的系统树显示2种梅童鱼在这2个基因片段上存在显著的遗传分化。根据Cytb基因2%/百万年的进化速率推断,棘头梅童鱼与黑鳃梅童鱼的分化时间约为550万年,发生于上新世(Pliocene)早期。
Collichthys lucidus and C. niveatus are commercially important fishery resources in China. Partial nucleotide sequences of mitochondrial DNA 16S rRNA and Cyt b gene fragments were sequenced and analyzed to study the relationship between C. luc/dus and C. niveatus. Forty-four nucleotide substitutions were detected among 16S rRNA （526 bp） and Cyt b （379 bp） fragments. Nucleotide composition analysis indicated that the content of guanine （G） was relatively low in the two fragments, especially at the third codon position of Cyt b genes. Average genetic distances based on 16S rRNA and Cyt b between C. lucidus and C. niveatus were 0. 012 and 0. 111, respectively. The phylogenetic tree showed that there was significant genetic divergence between C. luc/dus and C. niveatus. According to the evolutionary rate of 2% per one million years, the estimated divergence time between C. luc/dus and C. niveatus was 5.5 million years, which indicated an early Pliocene divergence for them.
出处
《南方水产》
2010年第2期13-20,共8页
South China Fisheries Science
基金
国家高技术研究发展计划(863计划)项目(2006AA09Z418)
国家自然科学基金项目(30471329)
