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Distribution of ploidy in prokaryotes and evolutionary advantages of polyploidy in prokaryotes

原核生物倍性的分布及原核生物多倍性的进化优势

基本信息

批准号：
56911144
负责人：
Professor Dr. Jörg Soppa
金额：
--
依托单位：
Arbeitskreis Biologie und Genetik von Prokaryonten
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2008
资助国家：
德国
起止时间：
2007-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/56911144?language=en
关键词：
Distribution ploidy prokaryotes evolutionary advantages

项目摘要

Eukaryotes are typically diploid, and some eukaryotic groups contain many polyploid species. In contrast, prokaryotes are generally believed to be monoploid and contain one molecule of a circular chromosome. However, recently it was discovered that two species of different genera of halophilic archaea are highly polyploid (Breuert, Allers, Spohn and Soppa 2006, PLoS ONE, e92). A literature survey revealed that the ploidy level has been determined only for a very limited number of species. More than half of them have several copies of the chromosome, indicating that polyploidy might be more widespread in prokaryotes than anticipated. One part of the project will address the distribution of polyploidy. The ploidy level will be determined for about 15 model species representing different phylogentic groups of bacteria. In addition, new isolates from environmental samples will be characterized, and it will be attempted to select for polyploid bacterial species. A second part of the project will address the evolutionary advantage of polyploidy. First, ploidy mutants of halophilic archaea will be selected that can be compared with the wildtype. The resistance against X-ray irradiation and desiccation will be characterized. It will be proven that intracellular polymorphism can yield a selective advantage under specific conditions, and gene conversion will be studied. Taken together, the project challenges the textbook view that prokaryotes are typically monoploid, and it will yield insight into the evolutionary advantage of polyploidy in prokaryotes.

真核生物通常是二倍体，一些真核生物群包含许多多倍体物种。相比之下，原核生物通常被认为是单倍体，含有一个环状染色体分子。然而，最近发现两种不同属的嗜盐古菌是高度多倍体的（Breuert, Allers, Spohn and Soppa 2006, PLoS ONE, e92）。一项文献调查显示，只有非常有限的物种才确定了倍性水平。其中一半以上有多条染色体，这表明多倍体在原核生物中的分布可能比预期的更为广泛。该项目的一部分将解决多倍体的分布问题。将确定代表不同系统发育群的大约15种模式物种的倍性水平。此外，从环境样品中分离的新菌株将被表征，并将尝试选择多倍体细菌物种。该项目的第二部分将探讨多倍体的进化优势。首先，选择嗜盐古菌的倍体突变体，与野生型进行比较。对x射线辐照和干燥的抗性进行表征。将证明细胞内多态性在特定条件下可以产生选择优势，并将研究基因转换。综上所述，该项目挑战了教科书上认为原核生物通常是单倍体的观点，并将深入了解原核生物多倍体的进化优势。