【作者】 卢海英；

【导师】 孙晖；

【作者基本信息】 东北师范大学 ， 遗传学， 2006， 硕士

【摘要】 本文采用基因组DNA的PCR产物克隆测序对8种中国北方鸢尾属植物和外类群射干的核DNA的ITS序列(包括ITS1、5.8s rDNA和ITS2)进行测定,结果表明鸢尾属ITS序列总长度为551bp-670bp,ITS1与ITS2均有较大长度变异,ITS1长度为195bp-258bp,ITS2长度为192bp-251bp,平均遗传距离为0.203, ITS序列在鸢尾属内显示出较大的变异程度。用PHYLIP软件进行系统发育分析和分子钟检验,分别用NJ法、ML法和MP法构建系统树表明:鸢尾属植物ITS序列特别适合解决属内近源种间系统分类问题,在乌苏里鸢尾和黄菖蒲间关系及乌苏里鸢尾的分类地位问题,支持将乌苏里鸢尾降为亚种处理。对于鸢尾属ITS序列的进行系统发育分析时,ML法和MP法两种基于特征符的建树方法更容易得到一致的结果。LR法检验分子钟假说证明鸢尾属ITS序列拒绝分子钟假说。更多还原

【Abstract】 The internal transcription spacers (include ITS1,5.8s rDNA and ITS2) of 8 species ofGenus Iris from North China and one outgroup Belamcanda.chinensis were sequenced. Itwas shown that the size of ITS of Iris is from 551bp to 670bp, the length variation was foundboth in ITS1 and ITS2. The length of ITS1 varies from 195bp to 258bp;the length of ITS2 isfrom 192bp to 251bp. The average genetics distance of ITS sequence of Iris is 0.203. Theoverall level of variation and sequence divergence is relatively high compared to otherinfragenetic plant group.In PHYLIP analysis, phylogenetic trees were reconstructed by using NJ method, MLmethod and MP method , and the molecular clock hypothesis was tested. The result supportsthat I.maackii should be a subspecies: I.pseudacorus L.subsp.maackii (Maxim.) M.Z.Sun etY.T.Zhao stat nov. Among the three methods of reconstructing phylogenetic trees by usingITS sequence of Iris, ML method and MP method are easier to get the same result than NJmethod. ITS sequence of Iris rejects the molecular clock hypothesis by likelihood ratio test.更多还原