【作者】 何利娜；

【导师】 廉振民； 乔格侠；

【作者基本信息】 陕西师范大学 ， 动物学， 2002， 硕士

【摘要】 蚜总科昆虫隶属于同翅目Homoptera蚜虫类Aphidinea，是同翅目中较大的一个类群。在蚜总科昆虫科级分类单元向系统发育研究中，目前存在不少问题。例如，刺蚜亚科Cervaphidinae属于毛管蚜科Greenideidae还属于群蚜科Thelaxidae；粉毛蚜亚科Pterocommatinae目前暂放在蚜科Aphididae内，但无论从形态学还是生物学、寄主植物等方面该亚科与毛蚜科Chaitophoridae有许多相似之处．从形态学等角度不能对上述问题得到圆满解答。因此，本研究拟将形态学特征与分子数据结合起来寻找最有效的解决方法。 rDNA是编码核糖体RNA的基因，18SrDNA被认为是研究高级分类阶元演化关系比较有效的基因，常用于科级水平的系统发育分析。本研究以越南、北京地区的蚜总科内代表蚜虫为主要研究对象，在依据外部形态分类鉴定的基础上，应用DNA序列测定技术于蚜总科昆虫系统学研究，通过PCR扩增获得蚜虫18SrDNA基因序列，应用Clustal W程序进行同源对比，采用MEGA 2．1数据分析软件，构建蚜总科蚜虫分子系统树，探讨这些类群这间的分类地位和亲缘关系，这在国内外尚属首次。 本研究通过对蚜总科内6科(4亚科)13种蚜虫18SrDNA基因序列的测定和分析，初步得出以下结论： 1、刺蚜亚科18SrDNA基因797bp的DNA序列中，A+T的平均含量为56.6％，群蚜科、刺蚜科和毛管蚜科的A+T含量分别为：52.5％、66.6％和51.9％，18SrDNA基因序列长分别为1100bp、760bp、1100bp。表明群蚜科与毛管蚜科近似。 2、MEGA2．1数据分析软件中构建的UPGMA、NJ、ME和MP分子系统树一致支持群蚜科和毛管蚜科形成一单系群，这二者相聚后与刺蚜亚科互为姐妹群。分子数据提示刺蚜亚科独立为一科。 3、蚜科内蚜亚科和长管蚜亚科的分化大于蚜科与毛蚜科之间的遗传分化。本研究选取扩增18SrDNA的600bp—1700bp这一区段不能完全解决粉毛蚜亚科的系统分类地位的归属。此1100bp序列在蚜科昆虫中变异程度比较大，包含一个高变区E21。更多还原

【Abstract】 Aphidinea are group of famous insects. They are harmful to agricultural plant. In the taxonomic study of Aphidiodea insects, there are some questions about them. In order to clarify the arguments for the phylogenetic relationships of Aphidinea insects, we determined a partial (HOObp) sequence of the 18S ribosomal DNA for 13 aphid species (4 subfamilies , 6 families) at the first time. They distributed mostly in China. In this study we studied the phylogenetic relationships of the two groups: Cervaphidinae and Pterocommatinae using the PCR product direct sequencing method. The respective outgroups Acyrthosium pisum and Lygus heperus Knight are the new gene informations for the International Biology Gene Bank.Here we got the ISSrDNA sequence data of the Aphidiodea, which were firstly aligned by Clustal W and then used to construct phylogenetic tree by MEGA 2.1. The result of Cervaphinae revealed that:㏕he sequence included 797bp in length. The average transition: transversion ratio was 1.0 which indicated the genetic differentiation was great. The ration was 2 in nuclear DNA gene. As a rule the ts:tv ratio decreased with the increasing genetic distance. ㏕he average A+T content is 56.6%. Among Thelaxiade .. Cervaphididinea and Greenideidae ,the A+T contained is 52.5?cK 66.6% and 51.9%,the length of the partial ISSrDNA was 1100bp> 760bp and llOObp respectively. It was found that a decreased in A+T content may has been accompanied by an increasing in length of the whole ISSrDNA gene sequence. (3)The phylogenetic tree by the method of UPGMAN MP> NJ and ME shows Thelaxiade is similar to Greenideidae and Cervaphidinae is a independent group.The studies on Pterocommatinae revealed that: The content of A+T in Aphididae is very variable. It was from 39.6% of A.pisum to 60.4% of Thxoptera odinae. It is clear that Pterocommatinae is closer to A.pisum. But there is ambiguously taxonomic position between Chaitophoridae and Aphidinae. The genetic distance of Aphididae and Macrosiphinae in Aphididae is more diverged than that of between Chaitophoridae and Aphididae. The 600bp-1700bp region of ISSrDNA gene maybe unsuitable to Aphididae, it includes a helix E21. The rate of evolution of in the region is a bit fast. It is necessary for the phylogenetic analysis that selecting suitable gene region, increasing the number of taxon and comparing more molecular markers.更多还原