新疆柔叶真藓居群18S核糖体RNA基因序列分析

Analysis of 18S rDNA Sequences of Bryum cellulare Hook.

柔叶真藓(Bryum cellulare Hook.)是真藓属植物。目前对分布在新疆阿尔金山国家级自然保护区不同地理居群的柔叶真藓遗传多样性研究还未见报道。本研究以采自于该保护区四个不同地理居群的柔叶真藓为样品对其18S核糖体RNA基因(18S r DNA)序列进行分析。结果表明:样本测序拼接完成后的序列长度在1 712~1 761 bp之间,进行空位剪切及比对后长度为1 698 bp。整个序列中有三个碱基位置上的差异,其中变异位点有12个,A、T、C、G的平均含量比率分别为24%、27%、23%、26%。再通过从NCBI的Gen Bank进行同源性搜索得到的相似性序列均属于真藓属,增大了序列的可靠性。将与其序列结合检测遗传距离及构建系统进化树,进行同源性分析可知,这种差异由于18S核糖体RNA基因序列本身的特性,表明种群的遗传距离与地理环境和位置有一定的相关性,其中在环境的变化及变异的可能性对四个不同地理居群的柔叶真藓植物有影响。

（Bryum cellulare Hook.） belongs to genus Bryum（Bryaceae）. At present, there is no report on the genetic diversity of different geographic populations of Bryum in the Altun mountains national nature reserve in Xinjiang. This study were conducted on 18 S ribosomal RNA gene sequence of collected from four different geographic populations of Bryum. The results showed that when the completing of the splicing of the sequences,the length of 18 S ribosomal RNA gene sequence was 1 712~1 761 bp; it was 1 698 bp when the completing of the cutting and comparison of the 18 S ribosomal RNA gene sequence. There are three base positions in the whole sequence, among which there are more than 12 mutation points. The average ratio of A, T, C and G were 24%,27%, 23% and 26% respectively. The homology sequences obtained from the homology search of NCBI Gen Bank belong to the genus Bryum which increases the reliability of the sequence. The sequence detection based on genetic distance, phylogenetic tree and homology analysis shows that this kind of differences due to characteristics of the 18 S ribosomal RNA gene sequence itself, that there is a certain correlation between the genetic distance of population and geographical environment and location, the possibility of changes in the environment and the variation of four different geographic populations of Bryun cellulare plants have affected.