Portrait of a species:: Chlamydomonas reinhardtii
Portrait of a species:: Chlamydomonas reinhardtii
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DOI：
10.1534/genetics.105.044503
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发表时间：
2005-08-01
期刊：
影响因子：
3.3
通讯作者：
Coleman, AW
中科院分区：
文献类型：
--
作者：
Pröschold, T;Harris, EH;Coleman, AW
莱茵衣藻是第一个基因组计划的藻类，是众多形态学、生理学和遗传学研究的对象。这种生物有两种基因决定的交配类型（正交配和负交配），简单生命周期的所有阶段都可以在培养中重现。自第一个标准实验室菌株分离以来的近60年中，实验室之间的大量杂交和交换导致了菌株谱系的混淆。在这里，我们利用核内部转录间隔区和其他遗传性状的分析来解决这些问题，正确识别目前可用的菌株，并分析与所有其他可用的类似衣原体类型的系统发育关系。在个体生物的一些核糖体反顺子拷贝中，ITS2中存在一个10-bp的索引，以及这些索引在杂交中的变化比例，为研究协同进化的机制提供了工具。标准菌株和C. smithii +以及北美东部新分离的C. reinhardiii菌株组成了一个形态种，一个有性亲和性高的生物学种，其ITS序列基本相同（ITS2的螺旋I尖端除外）。然而，不同的RFLP模式表征了每个地理位置的菌株。
Chlamydomonas reinhardtii, the first alga subject to a genome project, has been the object of numerous morphological, physiological, and genetic studies. The organism has two genetically determined mating types (plus and minus) and all stages of the simple life cycle can be evoked in culture. In the nearly 60 years since the first standard laboratory strains were isolated, numerous crosses and exchanges among laboratories have led to some confusion concerning strain genealogy. Here we use analyses of the nuclear internal transcribed spacer regions and other genetic traits to resolve these issues, correctly identify strains currently available, and analyze phylogenetic relationships with all other available similar chlamydomonad types. The presence of a 10-bp indel in ITS2 in some but not all copies of the nuclear ribosomal cistrons of an individual organism, and the changing ratios of these in crosses, provide a tool to investigate mechanisms of concerted evolution. The standard C. reinhardiii strains, plus C. smithii +, plus the new eastern North American C. reinhardiii isolates, comprise one morphological species, one biological species of high sexual intercompatibility, and essentially identical ITS sequences (except the tip of helix I of ITS2). However, variant RFLP patterns characterize strains from each geographic site.