摘要
为准确检测柔鱼（Ommαstrephesbartram川、茎柔鱼（ Dosidicus gigas）与阿根廷滑柔鱼（ IIIex argentinus ） 的种间遗传差异，对线粒体16SrRNA、细胞色素b（Cytb）与编码核糖体大亚基的基因（28SrDNA）片段序列进 行测定。经比对获得同源片段序列的长度分别为444、430、464坤，其中16SrRNA与28SrDNA基因片段上分别存在3处和47处碱基插入/缺失。核昔酸组成分析表明;3种柔鱼在3个基因片段上的核音酸组成差异不显著， 在线粒体2个基因片段上的A＋T含量（16SrRNA;69.90%、72.01%、74.66%; Cytb; 63.61%、68.91%、71.65% ） 均明显高于C＋C含量（16SrRNA;30.10%、27.99%、25.34%; Cytb; 36.39%、31.09%、28.35% ），而在28SrDNA 基因片段上的A＋T含量（37.16%、36.74%、38.29% ）明显低于C＋C含量（62.84%、63.26%、61.71 %）0 3种柔鱼 在28SrDNA基因片段上检测到的核昔酸替代率最低，为6.68%，而蛋白质编码基因Cytb核昔酸替代率最高，为 20.93%，核营酸替代均发生在密码子第3位点上，而且未引起氨基酸替代。基于邻接法、最大简约法与最大似然 法重建的系统树显示，柔鱼与茎柔鱼的亲缘关系较近。根据C严b基因片段序列分析，柔鱼与茎柔鱼和阿根廷滑柔鱼的分歧时间分别为653-790万a和765 - 925万a，种间分化事件发生在中新世至上新世间。
Ommastrephes bartramii, Dosidicus gigas and Illex argentinus are major fishing objects for China pelagic squid fishing industry. To evaluate the genetic variance of the three species, partial sequence of 16S rRNA, Cytb and 28S rDNA genes were amplified and sequenced. Three homologous fragments of 444 bp for 16S rRNA, 430 bp for Cytb and 464 bp for 28S rDNA genes were obtained by sequences aligning, and 3 and 47 insert-delete （indel） loci were found in the 16S rRNA and 28S rDNA gene fragments respectively. Result of nucleotide composition analysis indicated that no signal difference was detected in three gene fragments, and the AT content （16S rRNA： 69.90%, 72.01%, 74.66%; Cytb： 63.61%,68.91%,71.65%） was much higher than GC content （16S rRNA： 30.10%,27.99%, 25.34%; Cytb： 36.39%, 31.09%, 28.35%） in two mitochondria DNA fragments. On the contrary, it has much lower AT content （37.16%,36.74%,38.29%） than GC content （62.84%,63.26%, 61.71%） in 28S rDNA gene fragment whose nucleotide substitution rate was 6.68% in contrast to 20.93% in the protein coding gene of Cytb. All the nucleotide substitutions in Cytb gene fragment were occurred at the third codon positions without amino acid substitutions. Neighbor-Joining, Maximum-Parsimony and Maximum-likelihood phylogenetic trees all showed that the relationship between 0. bartramii and D. gigas was closer. Based on sequence analysis of partial Cytb gene, the estimated divergence time between 0. bartramii and D. gigas was 6.53-7.90 million years ago, while it was 7.65-9.25 million years ago between 0. bartramii and 1. argentinus, which might had occurred between Micene and Pliocene.
出处
《广东海洋大学学报》
CAS
2013年第6期24-29,共6页
Journal of Guangdong Ocean University
基金
国家自然科学基金(41276156)
上海市科委重大项目(12231203900)
国家发改委产业化专项(2159999)
关键词
柔鱼
线粒体基因
核核糖体基因
序列分析
分歧时间
Ommastrephidae
mitochondria DNA
nuclear ribosomal DNA
sequence analysis
divergence time
