The entire sequences of the ITS region of nuclear rDNA were determined from 9 diploid species in the genus Aegilops of Poaceae by direct double-sequencing. These sequences, together with the published ITS sequences, were analyzed using PHYLIP 3.5c package to assess the phylogenetic relationships in the genus Aegilops. The ITS regions and the coding region of 5.8S rDNA analyzed in the study were ranged from 601 to 607 bp in length, among them 75 variable sites were observed. The G+C content being, 61.1%-62.9%, is similar to most other species in Poaceae. The phylogenetic analysis of ITS sequences showed that there was no sister group relationships between Ae. speltoides and the other species of Section Sitopsis, thus suggesting that Ae. speltoides could be separated from the section. The phylogenetic trees also indicated that Ae.uniaristata in Section Comopyrum was more closely related to Ae.caudata and Ae.umbellulata than to the other members in this section, which was in general agreement with the previous cytogenetic results.
山羊草属二倍体物种核rDNA ITS 区序列及其系统发育关系分析
王超1 施苏华2 王建波1* 钟扬3
（1. 武汉大学生命科学学院，武汉430072；2. 中山大学生命科学学院，广州510275；3. 中国科学院武汉植物研究所，武汉430074）
摘要：测定了山羊草属（Ａｅｇｉｌｏｐｓ）二倍物种核ｒＤＮＡ ＩＴＳ区序列，发现其碱基粉介于６０１－６０７之间，比报道的小ｒｉｕｃｅａｅ）其他属的ＩＴＳ区我略长，Ｇ＋Ｃ含量达６１．１％～６２．９％，序列间的分化距离为０．００５０～０．０４６８。用ＰＨＹＬＩＰ３．５ｅ软件包对所测得的ＤＮＡ数据进行聚类分析，结果显示：１．Ａｅ．ｓｐｅｌｔｏｉｄｅｓ与该组其他种相距很远，支持将其从Ｓｉｔｏｐｓｉｓ组中独立出来， uniaristata不与同组的另两个物种聚在一起，却与Ae. caudata和Ae. umbellulata的关系很近，与以前对该属的细胞遗传学研究结果相似。
关键词： 山羊草属；ITS区序列；亲缘关系
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