毛蚜亚科线粒体基因组比较研究与系统发育关系重建

发布时间：2018-05-14 13:20

本文选题：毛蚜亚科 + 线粒体基因组　；参考：《河北大学》2017年硕士论文

【摘要】：昆虫线粒体基因组具有基因组短、基因排列相对稳定、进化速率快、普遍为母系遗传的特征,目前已成为研究物种进化和系统发育的重要分子标记。随着系统发育分析方法的日益成熟多样和测序技术的不断升级,以线粒体基因组为数据源的系统发育研究已成为焦点领域。基于线粒体基因组数据重建系统发育关系探讨昆虫系统发育的研究,主要集中在物种丰富度较高的目级和科级阶元水平,而针对于亚科及更低级阶元的研究甚少。通过比较发现,基于线粒体基因组的较高级阶元系统发育研究广泛存在无法避免的问题,如:长枝吸引、碱基替换饱和等,可导致分枝结构不理想。而亚科级及以下的低级阶元在分析过程中极少出现类似问题。因此,线粒体基因组对于解决低级阶元系统发育关系表现出更好的适应性。毛蚜亚科是半翅目蚜科的一个重要类群,包括2族,即毛蚜族和伪毛蚜族和12属,营同寄主全周期生活,而且两个族分别与木本植物和草本植物相关联,具有比较严格的寄主专化性。前期的研究主要集中在该亚科的物种鉴定与形态特征描述,寄主植物与生物学习性观察和地理分布等方面。有关该类群基于分子数据的相关研究很少,涉及的物种数量也非常有限;同时蚜虫线粒体基因组的获得相对比较困难,导致该亚科有关线粒体基因组的测序工作相对延迟,目前也没有关于毛蚜线粒体基因组的相关报道。规模化获取线粒体基因组信息,基于线粒体基因组数据重建毛蚜亚科内部系统发育关系,对了解毛蚜亚科的演化历史,探讨毛蚜与寄主植物之间的关系,推动蚜虫类线粒体基因组的研究水平具有重要意义。本研究选取毛蚜亚科2族8属22种,对毛蚜线粒体基因组进行测序、注释和比较分析,阐述毛蚜亚科线粒体基因组的基本特征;利用贝叶斯法(BI)和最大似然法(ML)构建系统发育树,重建毛蚜亚科的系统发育关系。主要研究结果如下:(1)获取21种蚜虫约87%-95%的基因组全长,序列长度13459-15384 bp,1个蚜虫(Trichaitophorus foliatus)获得了约65%的基因组,序列长度为10355 bp。对测序结果进行注释,表明基因排列方式与祖先排列方式一致,未发现基因重排现象。由于假基因的干扰和A+T含量高,大部分物种未能获得tRNAArg-nad5区域的序列。所有蛋白质编码基因的起始密码子都为ATN,终止密码子为TAA\TAG\T。间隔区大小范围为10-71bp,最大的重叠区位于atp6和atp8之间,大小为20 bp。(2)对毛蚜的碱基组成进行分析可知,A+T含量大于G+C含量,22个毛蚜物种A+T含量为81.55%-84.96%。在蛋白编码基因中,AT偏斜和GC偏斜都为负值,说明A少于T,G少于C。从密码子使用情况来看,Phe、Leu和Ile是编码最多的氨基酸,TTT(Phe)、TTA(Leu)和ATT(Ile)是使用次数最多的密码子。(3)以粉毛蚜Pterocomma pilosum(蚜科:粉毛蚜亚科)为参考,计算毛蚜物种的同义替换率Ks、非同义替换率Ka以及非同义替换率Ka与同义替换率Ks的比值Ka/Ks,所有的毛蚜Ka/Ks值小于1,说明受纯化选择。除三角枫多态毛蚜Periphyllus acerihabitans外,伪毛蚜族的进化速率要大于毛蚜族的进化速率。(4)利用BI和ML方法构建了毛蚜亚科系统发育树,两种方法构建的系统发育树拓扑结构一致。结果表明,在族级水平上,毛蚜族和伪毛蚜族的单系性得到了支持。在伪毛蚜族内,小毛蚜属和伪毛蚜属的物种聚在一起,因此使其成为并系群。赖毛蚜属的单系性成立并且位于伪毛蚜族的基部位置;在毛蚜族中,多态毛蚜属的Periphyllus acerihabitans和Periphyllus acericola与毛蚜族的其他物种形成姐妹群,在毛蚜族的其他物种中,三毛蚜属和桠毛蚜属的单系性得到了支持并与多态毛蚜属的物种聚为一支,形成((Trichaitophorus+Yamatochaitophorus)+Periphyllus)的姐妹群关系。朗伯毛蚜属的Lambersaphis pruinosa聚到毛蚜属内,使毛蚜属成为并系群。
[Abstract]:The genome of insect mitochondrial genome has short genome, relatively stable gene arrangement and rapid evolution rate. It has become an important molecular marker for the study of phylogenetic and phylogeny. With the growing diversity of phylogenetic analysis and the continuous upgrading of sequencing technology, the mitochondrial genome is the data. Phylogenetic studies of sources have become the focus areas. Based on the relationship between mitochondrial genome data reconstruction and phylogenetic relationships, the study of insect phylogeny mainly focuses on the level of higher species richness and the level of the rank of the science level, while the needles are seldom studied for subfamilies and lower order elements. There are many unavoidable problems in the research of higher order system development, such as long branch attraction, base substitution saturation, etc., which can lead to the undesirable branch structure, and the subdivision and lower order elements rarely appear similar problems in the analysis process. Therefore, the mitochondrial genome is better in solving the relationship of low order system development. The aphis Aphis subfamily is an important group of Hemiptera aphis, including 2 ethnic groups, namely, the aphid and the pseudoraphis and 12 genera, the camps and the host are all cycle life, and the two families are related to the woody plants and herbaceous plants, with a strict host specialization. The previous study mainly focused on the species identification and shape of the subfamily. There are few related studies on molecular data and the number of species involved in this group are very limited. At the same time, the acquisition of the mitochondrial genome of aphids is relatively difficult, which leads to the relatively delayed sequencing of the mitochondrial genome of the subfamily. There is no related report on the mitochondrial genome of the aphid. To obtain the mitochondrial genome information in scale, to reconstruct the internal phylogenetic relationship of the subfamily Mao by the mitochondrial genome data, to understand the evolution history of the aphis Aphis and to explore the relationship between the aphid and the host plant, and to promote the research level of the mitochondrial genome of the aphid. It is of great significance. In this study, 2 families and 8 genera of Aphis hairy subfamily were selected. The mitochondrial genome of aphid was sequenced, annotated and analyzed, and the basic characteristics of the mitochondrial genome of Aphis hairy family were described. The phylogenetic tree was constructed by BI and ML, and the phylogenetic relationship of the subfamily hairy aphid was rebuilt. As follows: (1) the total length of the genome of about 87%-95% of 21 aphids was obtained, the length of the sequence was 13459-15384 BP, and the 1 aphids (Trichaitophorus foliatus) obtained about 65% of the genome, and the sequence length was 10355 bp. to annotate the sequencing results, indicating that the gene arrangement was in accordance with the ancestor row mode, and the gene rearrangement was not found. The pseudogenes were not found. The interference and A+T content were high, most of the species failed to obtain the sequence of the tRNAArg-nad5 region. The initial codon of all the protein encoding genes was ATN, the size of the terminating codon was 10-71bp, the largest overlap area was between Atp6 and ATP8, and the size was 20 bp. (2) for the analysis of the base composition of the aphid. The A+T content of 22 aphids was 81.55%-84.96%. in the protein encoding gene, AT bias and GC skew were negative, indicating that A was less than T, G was less than C., Phe, Leu and Ile were the most coded amino acids. MMA pilosum (aphid: aphid subfamily) was used as a reference to calculate the synonymous substitution rate of Ks, the non synonymous substitution rate Ka and the ratio Ka/Ks of the non synonymous substitution rate Ka to the synonymous substitution rate Ks, and the Ka/Ks value of all the aphids was less than 1, indicating that the phylogenetic rate of the pseudo Maple aphid, except for the Periphyllus acerihabitans of the trigonometric Maple aphid (4) the phylogenetic tree of the aphis Maoist subfamily was constructed by BI and ML, and the phylogenetic tree of the two methods was consistent. The results showed that the monophyleties of the aphid and pseudohairy aphids were supported at the ethnic level. In the pseudoaphid family, the species of the genus Aphis and pseudoaphid were gathered together. A single lineage of the genus lysia and located at the base of the pseudoraphis tribe; in the aphid, the Periphyllus acerihabitans and Periphyllus acericola of the polymorphic aphids form sister groups with other species of the aphid, and in the other species of the aphid, the monophylle of the genus triapid and the genus APHIS. To support and gather with the species of the polymorphic genus Maoist, the sister group relationship of ((Trichaitophorus+Yamatochaitophorus) +Periphyllus) is formed. The Lambersaphis pruinosa of the genus hairy aphid is clustered into the genus hairy aphid and makes the genus Aphis genera.

【学位授予单位】：河北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q963

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