Wang Zheng, Wang Yen-Wen, Kasuga Takao, Hassler Hayley, Lopez-Giraldez Francesc, Dong Caihong, Yarden Oded, Townsend Jeffrey P
Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA.
College of Biological Sciences, University of California, Davis, Davis, California, USA.
Mol Ecol. 2024 Dec;33(24):e17168. doi: 10.1111/mec.17168. Epub 2023 Oct 16.
The origin of new genes has long been a central interest of evolutionary biologists. However, their novelty means that they evade reconstruction by the classical tools of evolutionary modelling. This evasion of deep ancestral investigation necessitates intensive study of model species within well-sampled, recently diversified, clades. One such clade is the model genus Neurospora, members of which lack recent gene duplications. Several Neurospora species are comprehensively characterized organisms apt for studying the evolution of lineage-specific genes (LSGs). Using gene synteny, we documented that 78% of Neurospora LSG clusters are located adjacent to the telomeres featuring extensive tracts of non-coding DNA and duplicated genes. Here, we report several instances of LSGs that are likely from regional rearrangements and potentially from gene rebirth. To broadly investigate the functions of LSGs, we assembled transcriptomics data from 68 experimental data points and identified co-regulatory modules using Weighted Gene Correlation Network Analysis, revealing that LSGs are widely but peripherally involved in known regulatory machinery for diverse functions. The ancestral status of the LSG mas-1, a gene with roles in cell-wall integrity and cellular sensitivity to antifungal toxins, was investigated in detail alongside its genomic neighbours, indicating that it arose from an ancient lysophospholipase precursor that is ubiquitous in lineages of the Sordariomycetes. Our discoveries illuminate a "rummage region" in the N. crassa genome that enables the formation of new genes and functions to arise via gene duplication and relocation, followed by fast mutation and recombination facilitated by sequence repeats and unconstrained non-coding sequences.
新基因的起源长期以来一直是进化生物学家关注的核心问题。然而,它们的新颖性意味着它们无法通过进化建模的经典工具进行重建。这种对深入祖先研究的规避使得有必要对采样充分、近期分化的进化枝中的模式物种进行深入研究。一个这样的进化枝是模式属脉孢菌属,其成员缺乏近期的基因重复。几种脉孢菌物种是全面表征的生物体,适合研究谱系特异性基因(LSGs)的进化。利用基因共线性,我们记录到78%的脉孢菌LSG簇位于端粒附近,这些端粒具有大量的非编码DNA和重复基因。在这里,我们报告了几个可能来自区域重排且可能来自基因重生的LSG实例。为了广泛研究LSGs的功能,我们从68个实验数据点组装了转录组学数据,并使用加权基因共表达网络分析确定了共调控模块,结果表明LSGs广泛但边缘地参与了多种功能的已知调控机制。我们详细研究了在细胞壁完整性和细胞对抗真菌毒素敏感性方面起作用的基因LSG mas-1与其基因组邻居的祖先状态,表明它起源于一个古老的溶血磷脂酶前体,该前体在粪壳菌纲的谱系中普遍存在。我们的发现揭示了粗糙脉孢菌基因组中的一个“翻找区域”,该区域能够通过基因复制和重新定位形成新基因和新功能,随后通过序列重复和无约束的非编码序列促进快速突变和重组。