Acs-Szabo Lajos, Papp Laszlo Attila, Sipiczki Matthias, Miklos Ida
Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary.
J Fungi (Basel). 2021 Oct 14;7(10):864. doi: 10.3390/jof7100864.
Fission yeasts have a unique life history and exhibit distinct evolutionary patterns from other yeasts. Besides, the species demonstrate stable genome structures despite the relatively fast evolution of their genomic sequences. To reveal what could be the reason for that, comparative genomic analyses were carried out. Our results provided evidence that the structural and sequence evolution of the fission yeasts were correlated. Moreover, we revealed ancestral locally collinear blocks (aLCBs), which could have been inherited from their last common ancestor. These aLCBs proved to be the most conserved regions of the genomes as the aLCBs contain almost eight genes/blocks on average in the same orientation and order across the species. Gene order of the aLCBs is mainly fission-yeast-specific but supports the idea of filamentous ancestors. Nevertheless, the sequences and gene structures within the aLCBs are as mutable as any sequences in other parts of the genomes. Although genes of certain Gene Ontology (GO) categories tend to cluster at the aLCBs, those GO enrichments are not related to biological functions or high co-expression rates, they are, rather, determined by the density of essential genes and Rec12 cleavage sites. These data and our simulations indicated that aLCBs might not only be remnants of ancestral gene order but are also maintained by natural selection.
裂殖酵母具有独特的生活史，并且展现出与其他酵母不同的进化模式。此外，尽管其基因组序列进化相对较快，但该物种的基因组结构却很稳定。为了揭示其中的原因，我们进行了比较基因组分析。我们的结果表明，裂殖酵母的结构和序列进化是相关的。此外，我们发现了祖先局部共线区域（aLCBs），这些区域可能是从它们的最后一个共同祖先遗传而来的。这些aLCBs被证明是基因组中最保守的区域，因为在不同物种中，aLCBs平均每个区域包含近八个基因/区域，且基因排列方向和顺序相同。aLCBs的基因顺序主要是裂殖酵母特有的，但支持丝状祖先的观点。然而，aLCBs内的序列和基因结构与基因组其他部分的序列一样容易发生突变。虽然某些基因本体论（GO）类别的基因倾向于聚集在aLCBs，但这些GO富集与生物学功能或高共表达率无关，相反，它们是由必需基因的密度和Rec12切割位点决定的。这些数据和我们的模拟表明，aLCBs可能不仅是祖先基因顺序的残余，而且还受到自然选择的维持。
