Dyer P S, Paoletti M
School of Biology, University of Nottingham, Nottingham, UK.
Med Mycol. 2005 May;43 Suppl 1:S7-14. doi: 10.1080/13693780400029015.
Aspergillus fumigatus has long been considered to reproduce only by asexual means. However, accumulating evidence suggest that a sexual stage for A. fumigatus may yet be identified. We describe results from published and ongoing studies involving population genetic analyses, genome analysis, studies of mating-type gene presence and distribution, expression of sex-related genes, and taxonomic work which support the assertion that A. fumigatus has the potential to reproduce by sexual means. The consequences of sexual reproduction for the population biology and disease management of the species are discussed. The possible mechanisms of evolution of asexuality are then considered. It is proposed that asexual species may arise in one step by mutation or loss of a key gene(s), and/or there may be a 'slow decline' in sexual fertility within the species as a whole. Thus, it is argued that species should not be considered simply as sexual or asexual, but rather as individual isolates being present on a continuum of sexual fertility, with the implications for understanding sexuality/asexuality in A. fumigatus discussed.
长期以来，烟曲霉一直被认为仅通过无性方式繁殖。然而，越来越多的证据表明，烟曲霉的有性阶段可能仍有待确定。我们描述了已发表和正在进行的研究结果，这些研究涉及群体遗传分析、基因组分析、交配型基因的存在与分布研究、性别相关基因的表达以及分类学工作，这些研究支持了烟曲霉具有通过有性方式繁殖的潜力这一论断。讨论了有性繁殖对该物种群体生物学和疾病管理的影响。接着考虑了无性繁殖进化的可能机制。有人提出，无性物种可能通过关键基因的突变或缺失一步形成，和/或在整个物种中，有性繁殖能力可能会出现“缓慢下降”。因此，有人认为，物种不应简单地被视为有性或无性，而应看作是处于有性繁殖能力连续统一体上的个体分离物，并讨论了这对理解烟曲霉有性/无性的意义。
