香港红山茶个体内ITS多态性及物种鉴定的应用  

Intragenomic Polymorphism of the Internal Transcribed Spacer Region of Ribosomal DNA in Camellia hongkongensis(Theaceae) and Species Identification

作　　者：范文[1] 徐颖[1] 许汀[1] 徐晶[1,2] Takahiro Yonezawa 高继银 张文驹[1] 

机构地区：[1]复旦大学生命科学学院生物多样性科学研究所,生物多样性与生态工程教育部重点实验室,上海200433 [2]中国科学院上海生命科学信息中心,上海200031 [3]广东棕榈风景园林科学研究院,中山528416

出　　处：《植物学报》2015年第2期217-226,共10页Chinese Bulletin of Botany

基　　金：国家重点基础研究发展规划(No.2007CB411600)

摘　　要：核糖体DNA的内转录间隔区(ITS)一直被作为一种重要的分子标记,却很难用于山茶物种中。通过对1个疑似香港红山茶(Camellia hongkongensis)的样本进行ITS区域的扩增、克隆和测序,从中获得74种不同序列。研究结果表明,其ITS区域具有高度的多态性,其中76%的序列为假基因。系统发育分析显示,超过半数的假基因源自同一祖先。这些假基因在经历多次基因重复后分化成至少5个谱系,且每个谱系中的序列非常相似,这表明一些假基因不但未被剔除,反而通过快速复制事件幸存下来。由于山茶物种个体内ITS的高度多态,使用这个区域区分山茶物种可能导致错误。然而,通过比较香港红山茶中的1个种间特异性r DNA假基因,确定该样本属于香港红山茶。The internal transcribed spacer （ITS） region of ribosomal DNA has been selected as an important barcoding region in plants, but its use in Camellia species is difficult. In this study, we amplified, cloned and sequenced the ITS region of a Camellia plant from Vietnam that was similar to C. hongkongensis and obtained 74 sequences from an indi- vidual. The ITS region showed high polymorphism within the individual, and 76% of the sequences were pseudogenes. Phylogenetic analysis showed that more than half of the pseudogenes originated from a common ancestor. These older rDNA pseudogenes differentiated into at least 5 lineages after repeated gene duplication, and sequences in each lineage were similar to each other, which suggests that some pseudogenes had not been deleted but had recently undergone rapid duplication events. The high polymorphism of the ITS region within an individual in Camellia species would likely result in faulty identities when using this region as a barcode. However, by comparing the species-specific rDNA pseu- dogenes in C. hongkongensis, we identified the sample from Vietnam that belongs to C. hongkongensis.

关 键 词：香港红山茶 内转录间隔区(ITS) 系统发育 多态性 假基因 

分 类 号：S685.14[农业科学—观赏园艺]