基于16SrDNA和COII基因序列的蝗总科部分种类分子系统学研究

发布时间：2018-09-09 11:36

【摘要】：蝗总科昆虫是直翅目的重要组成部分,也在食物链中扮演着多种角色,对维持生态系统稳定有不可替代的作用。蝗总科昆虫对农业、牧业和林业的发展有巨大影响,与人类生活息息相关,所以对蝗总科的研究意义重大。在蝗总科的研究中,系统学一直是研究的热点。传统分类学主要以形态为依据,已经不能满足现代研究的要求。本研究采用酚-氯抽提、PCR扩增和DNA测序等手段,辅助以Bio Lign、MEGA5.05、PAUP4.0、Mr Bayes3.1.2等软件,对剑角蝗科、斑翅蝗科、槌角蝗科和斑腿蝗科16种蝗虫的16Sr DNA和COII基因,进行序列组成分析、碱基替换分析、密码子使用分析、氨基酸组成分析、遗传距离分析和碱基替换饱和度分析,并最后以短额负蝗为外群,采用ML、MP、NJ、BI法,分别对16Sr DNA基因、COII基因和两个基因联合构建系统发育树,进行分子系统学研究。通过研究分析,得到以下主要结论:(1)蝗总科线粒体基因具有明显A+T偏向性,其中16Sr DNA基因A+T含量为71.2%,COII基因A+T含量为71.8%。(2)16Sr DNA基因保守性为66.5%,COII基因保守性为53.2%。16Sr DNA基因比COII基因更保守。同时,基因中的第三位点的变异容易被保留下来,所以第三位点变异率更高。(3)COII基因中出现频率较高的密码子为AUU(21.3)、UUA(17)和ACA(12.1),而CUG、UCG和GCG没有出现,密码子出现频率的差异可能与线粒体内相应种类t RNA含量有关。含量较高的氨基酸为异亮氨酸(11.57)、亮氨酸(11.49)和丝氨酸(9.72)。(4)16种蝗虫的16Sr DNA基因的非矫正遗传距离在0.006-0.151之间。16种蝗虫的COII基因的非矫正遗传距离范围在0.007-0.236之间。(5)通过建立遗传距离与R值、TS、TV的关系,证明该两个基因的碱基替换没有达到饱和。(6)在系统发育关系上,剑角蝗科、斑翅蝗科、槌角蝗科和斑腿蝗科互为单系群。红翅皱膝蝗与鼓翅皱膝蝗亲缘关系较近,但不是一个物种(支持率95)。黄胫小车蝗并没有和亚洲小车蝗形成姊妹群,而是与轮纹异痂蝗亲缘关系更近。本论文通过测定16种蝗虫的16Sr DNA和COII基因序列,对其进行系统发育分析,为蝗虫的系统分类提供了分子依据。后续工作中将增加蝗虫种类,加大扩增片段长度,以获得更可靠的系统发育信号。
[Abstract]:Acridae is an important part of Orthoptera and plays a variety of roles in the food chain, which plays an irreplaceable role in maintaining ecosystem stability. Acridae insects have great influence on the development of agriculture, animal husbandry and forestry, and are closely related to human life, so the research on Acridae is of great significance. Systematics has always been a hot topic in the studies of Acridoidea. Traditional taxonomy is mainly based on morphology and can not meet the requirements of modern research. In this study, the 16Sr DNA and COII genes of 16 species of grasshopper of the family Acridoidea, Acridae, Acridae and Acridae were sequenced and analyzed by means of phenol-chlorine extraction PCR amplification and DNA sequencing, and Bio Lign,MEGA5.05,PAUP4.0,Mr Bayes3.1.2 software was used to analyze the 16Sr DNA and COII genes of 16 species of grasshopidae. Base substitution analysis, codon usage analysis, amino acid composition analysis, genetic distance analysis and base substitution saturation analysis were used. Finally, ML,MP,NJ,BI method was used. The phylogenetic tree was constructed by 16Sr DNA gene and two genes, and the molecular phylogeny was studied. The main conclusions are as follows: (1) Mitochondrial genes of Acridoidea have obvious A-T bias. The A T content of 16Sr DNA gene was 71.2 and that of COII gene was 71.8. (2) the conserved nature of 16Sr DNA gene was 66.5%. 53.2%.16Sr DNA gene was more conserved than COII gene. At the same time, the variation of the third locus in the gene is easy to be preserved, so the mutation rate of the third locus is higher. (3) the codon with higher frequency in COII gene is AUU (21.3) UUA (17) and ACA (12.1), but CUG,UCG and GCG do not appear. The difference of codon frequency may be related to the content of t RNA in mitochondria. The higher amino acids were isoleucine (11.57), leucine (11.49) and serine (9.72). (4). The uncorrected genetic distance of 16Sr DNA gene of 16 locust species was 0.006-0.151. The uncorrected genetic distance of COII gene of 16 species locust was 0.007-0.236. The relationship between genetic distance and R value of TSTV. It is proved that the base substitution of the two genes is not saturated. (6) the phylogenetic relationships of the two genes are monophyletic. The phylogenetic relationship between Gymnochus rotundii and A. typhus was close, but it was not a species (support rate 95). It was not a sister group with the Asiatic locust, but more closely related to the whorl heteroglyphagus locust. In this paper, the 16Sr DNA and COII genes of 16 species of locusts were sequenced and phylogenetic analysis was carried out, which provided molecular basis for the systematic classification of locusts. In the following work, the species of locusts and the length of amplified fragments will be increased to obtain more reliable phylogenetic signals.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S433.2

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