【摘要】 本研究参照GeneBank中禾本科植物大麦5S rDNA序列,利用PCR技术扩增获得新疆7个小麦种5S rDNA部分序列,进一步与禾本科植物大麦5S rRNA序列比对,得到了5S rDNA结构和NTS边界范围。序列分析发现,不同类型小麦5S rDNA序列保守程度不同,其中大片段保守性较高,小片段相对较低,7个小麦种5S rDNA序列均存在不同程度的插入和缺失序列,同种不同类型和不同种5S rDNA非转录间隔区(NTS)长度和存在位置均呈现不同程度差异。利用MEGA4.0软件,采用邻接法(NJ)和最大简约法(MP)构建分子进化树并计算种间遗传距离。以7个小麦种进化关系的分析结果为依据,利用5S rDNA两种类型片段建立了两种不同的亲缘关系分类依据,旨在为新疆7个小麦种亲缘关系分析提供一定理论依据,以期为后期种间同源关系分析,建立序列集合,推导系统进化与发育关系,重建发育史和遗传育种奠定一定理论依据。更多还原

【Abstract】 Referring GeneBank in barley grasses 5S rDNA sequences, partial 5S rDNA sequences from several accessions of 7 wheat species from Xinjiang were obtained by polymerase chain reaction, the 5S rDNA structure and NTS boundaries were obtained by further alignments with barley grasses 5S rRNA sequence. Sequence analysis revealed that the degree of the nontranscribed spacer of the different unit classes was different. The nontranscribed spacer of long repeat classes was less variable than that of short repeat classes. Different degrees of insertion and deletion in 5S rDNA sequences of 7 wheat species from Xinjiang was presented and the different degree of difference was presented in 5S rDNA non-transcribed spacer(NTS) length and position exists in different repeats of one species and different species. Molecular phylogenetic tree was constructed and genetic distance between species was calculated by using the MEGA4.0 software, the neighbor-joining method(NJ) and the maximum parsimony(MP). On the basis of evolutionary relationships analyzed results in seven wheat species, the foundation of two different phylogenetic relationship classification was established by two types of units of 5S rDNA.These results provides certain theoretical foundation for the phylogenetic analyses of 7 Xinjiang wheat species, the later period homology analyses, the sequence establishment, the phylogenetic relationship deduction, the phylogenetic reconstruction and the genetic breeding.更多还原