5S ribosomal RNA genes in six species of Mediterranean grey mullets: Genomic organization and phylogenetic inference
5S ribosomal RNA genes in six species of Mediterranean grey mullets: Genomic organization and phylogenetic inference
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DOI：
10.1139/g07-058
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发表时间：
2007-09-01
期刊：
影响因子：
3.1
通讯作者：
Annesi, Flavia
中科院分区：
文献类型：
--
作者：
Gornung, Ekaterina;Colangelo, Paolo;Annesi, Flavia
本文对4属6种牡蛎的5S核糖体RNA基因(5S RDNA)进行了研究。在这6个物种中，由聚合酶链式反应产生的相对较短的5S rDNA重复单位，大小在219-257bp之间，显示出编码区和间隔区(NTS-I)高度的基因组内同源性。基于这一数据集的系统发育重建突出了与Liza属和Chelon属相比，Mugil cephalus和Oedalechilus labeo的系统发育和遗传多样性更大。比较序列分析表明，车兰和丽莎的短5S rDNA重复单位具有显著的保守性。此外，在Liza和车兰样品中还产生了第二类5S rDNA重复单位，大约从800到1100个碱基对不等。在头鳍金鱼和罗非鱼中只发现了短的5S rDNA重复单位。在长5S rDNA重复单元的序列中，由于在间隔区(NTS-II)中存在两个大的插入/缺失(INDel)，所以它们的序列不同，并且显示出与NTS-I间隔区的相当大的序列相似性。除INDELs外，NTS-II间隔区的种间序列变异较小。Souome-Blot杂交模式表明，在单个染色体位置上，短重复单位和长重复单位混合排列。
This paper describes a study of the 5S ribosomal RNA genes (5S rDNA) in a group of 6 species belonging to 4 genera of Mugilidae. In these 6 species, the relatively short 5S rDNA repeat units, generated by PCR and ranging in size from 219 to 257 bp, show a high level of intragenomic homogeneity of both coding and spacer regions (NTS-I). Phylogenetic reconstructions based on this data set highlight the greater phylogenetic and genetic diversity of Mugil cephalus and Oedalechilus labeo compared with the genera Liza and Chelon. Comparative sequence analysis revealed significant conservation of the short 5S rDNA repeat units across Chelan and Liza. Moreover, a second size class of 5S rDNA repeat units, ranging from roughly 800 to 1100 bp, was produced in the Liza and Chelan samples. Only short 5S rDNA repeat units were found in M. cephalus and O. labeo. The sequences of the long 5S rDNA repeat units, obtained in Chelon labrosus and Liza ramada, differ owing to the presence of 2 large insertion/deletions (indels) in the spacers (NTS-II) and show considerable sequence identity with NTS-I spacers. Interspecific sequence variation of NTS-II spacers, excluding the indels, is low. Southem-blot hybridization patterns suggest an intermixed arrangement of short and long repeat units within a single chromosome locus.