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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。
In this study, 5S rDNA sequences of gramineous barley in GeneBank were used to amplify the 5S rDNA sequence of 7 wheat cultivars in Xinjiang by PCR. The 5S rDNA sequence of barley was further compared with that of 5S rRNA in gramineous plants. The 5S rDNA structure and NTS boundary . Sequence analysis showed that 5S rDNA sequences of different types of wheat were conserved in different degrees, among which the large fragments were highly conserved and the small fragments were relatively low. The 5S rDNA sequences of 7 wheat cultivars all had different degrees of insertion and deletion sequences, Different 5S rDNA non-transcribed spacer (NTS) length and location showed varying degrees of difference. The MEGA4.0 software was used to construct the phylogenetic tree using neighbor-joining (NJ) and maximal parsimony (MP) methods and to calculate the interspecific genetic distance. Based on the analysis of the evolutionary relationships of seven wheat cultivars, two different types of 5S rDNA fragments were used to establish two different taxonomic relationships to provide a theoretical basis for the genetic relationship analysis of seven wheat cultivars in Xinjiang. The establishment of sequence collection, deducing the relationship between phylogenetic evolution and development, reconstructing phylogenetic history and genetic breeding.