11种鲈形目鱼类的核糖体基因GC含量及其与硬骨鱼类的特征比较

发布时间：2018-03-29 05:39

本文选题：编码基因　切入点：间隔区　出处：《中国水产科学》2017年04期

【摘要】：核糖体基因为串联重复多拷贝的基因,包括3个编码基因(18S,5.8S,28S)和两个间隔区ITS1(internal transcribed spacer 1)和ITS2(internal transcribed spacer 2)。目前,对核糖体基因的相关报道主要集中在个体内不同拷贝间的多态特征,以及其作为分子标记在系统演化关系中的应用,GC含量作为一项非常重要的核苷酸序列指标,而鲜有报道。为了探讨鱼类的核糖体基因GC含量特征以及间隔区是否也存在GC平衡现象,本研究选择了鲈形目(Perciformes)5科11种鱼类5个片段的核糖体基因进行研究,包括尖吻鲈科(Latidae)、射水鱼科(Toxotidae)、军曹鱼科(Rachycentridae)、剑鱼科(Xiphiidae)、湽科(Carangidae)。获得了1651个单克隆序列,通过分析并比较已有的其他硬骨鱼序列片段的GC含量变化特征,结果发现:本研究鱼类的18S的GC含量为52.6%~57.1%(平均54.6%),5.8S为55.6%~58.9%(平均57.4%),28S为64.2%~65.8%(平均64.6%),ITS1为56.5%~73.0%(平均65.0%),ITS2为62.3%~77.5%(平均69.1%)。编码区的GC含量相对较保守,变异范围较小,18S和5.8S变化范围明显小于间隔区,28S则位于间隔区的最低值和最高值之间。因此,我们发现硬骨鱼核糖体ITS高于60%的GC含量是该类群的一个特征,并且高GC含量的ITS1和ITS2序列中不存在明显的高GC富集区,其含量高低的变化与序列长度也没有相关性。本研究11种鱼类的ITS1和ITS2的GC含量在种内的相似性既有大于也有小于种间相同片段的相似性,因此GC平衡现象只存在部分种类中。本研究结果可为鱼类核糖体基因序列特征的进一步研究及利用提供科学依据。
[Abstract]:Ribosomal gene is due to multiple copies of tandem repeat genes, including three coding genes 18 S5. 8 S5 / 28S) and two spacers, ITS1(internal transcribed spacer 1) and ITS2(internal transcribed spacer 2. At present, the related reports of ribosomal genes mainly focus on the polymorphic characteristics of different copies in individuals. And its application as molecular marker in phylogenetic relationships GC content is a very important index of nucleotide sequence. In order to study the characteristics of ribosomal gene GC content and the existence of GC equilibrium in the spacer region, the ribosomal genes of 5 fragments from 11 fishes belonging to 5 families of Perciformesus perciformes were studied in this study. Including Latidaeidae, Toxotidaeae, Rachycentridaeae, Xiphiidaeae, Carangida dae. 1651 monoclonal sequences were obtained, and the GC content characteristics of other bone fish sequences were analyzed and compared. The results showed that the GC content of 18s in the fish in this study was 52.67.1. (the average value of 54.66.8S was 55.68.9S (57.40.28s was 64.25.8S). The average value of ITS1 was 56.53.0 (the average 65.0ITS2 was 62.37.57.5.) the GC content in the coding area was relatively conservative. The variation ranges of 18s and 5.8s were significantly smaller than those of the spacer, which were between the lowest and highest values of the spacer region. Therefore, we found that the GC content of the ribosome above 60% is a characteristic of this group. Moreover, there is no obvious high GC rich region in ITS1 and ITS2 sequences with high GC content. There was no correlation between the variation of ITS1 content and sequence length. In this study, the similarity of GC content of ITS1 and ITS2 in 11 species of fish was greater than that of the same fragment in different species. Therefore, GC equilibrium exists only in some species. The results of this study can provide scientific basis for further study and utilization of ribosomal gene sequence characteristics in fish.
【作者单位】：中国科学院热带海洋生物资源与生态重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(31272273;41276166)
【分类号】：S917.4

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