低基因拷贝数表明,状菌根菌在遗传上继承了不同的基因核
1Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland.
Nature
|January 15, 2005
概括
树状菌根真菌 (AMF) 具有遗传上不同的核,挑战了它们的变异仅仅来自高 ploidy 的概念. 这一发现为这些古老的共生生物体的基因组进化提供了新的见解.
科学领域:
- 菌类学 菌类学是指菌类学.
- 进化生物学 进化生物学
- 基因组学就是基因组学.
背景情况:
- 树枝状菌根真菌 (AMF) 是关键的共生生物体,参与植物营养和多样性.
- AMF是古老的,无性繁殖的真核生物,但它们的基因组组织和进化仍然不太清楚.
- 在AMF中的遗传变异被归因于高性,但这个假设缺乏强有力的证据.
研究的目的:
- 调查AMF种群变异的遗传基础.
- 为了确定遗传变异是否是由于高 ploidy 或其他机制.
- 为 AMF 中核之间的遗传差异提供最清晰的证据.
主要方法:
- 在AMF中分析Pol-like序列中的遗传变异.
- 核DNA含量的评估,以评估性水平.
- 观察到的遗传变异与高 ploidy 和基因重复模型的预测进行比较.
主要成果:
- 在AMF的遗传变异,特别是在Pol-like序列中,并不能通过高 ploidy 或基因重复来解释.
- 在AMF内的核之间存在显著的遗传差异,证实了异质菌症.
- 发现含有大量核DNA的AMF是平体,而不是多体.
结论:
- 由于遗传上不同的核的共存 (异质核病),AMF表现出显著的遗传变异.
- 这一发现驳斥了高性是AMF遗传多样性的主要驱动因素的假设.
- 在AMF中独特的基因组组织对理解真核生物和共生生物体中基因组动态的进化有着深刻的影响.
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