近縁種で独立に生じた全ゲノム重複が解明する全ゲノム重複のメカニズムとインパクト

在这个项目中，我们的目标是了解新功能化和亚功能化是如何发生的，以及它们是由特定的遗传元件还是基因组多倍化后附近基因的功能驱动的。在新测序的真菌基因组中基因组多倍化的鉴定和表征之后，我们研究了直系同源物和旁系同源物之间的进化速率，新形成的相邻基因的转录方向，以及蛋白质复合物和生物途径组分的化学计量的保守性。今年，我们报告了在真菌属毛孢子菌的单一进化枝内发现了两个最近且独立的基因组杂交。比较基因组分析显示，冗余基因正在经历进化速度的减速，而不是加速。我们确定了基因转换和进化减速之间的关系，表明基因转换可能会提高基因组的稳定性，年轻的杂种限制基因功能的分歧。此外，我们检测到大规模的基因损失的转录和翻译机制，表明全球补偿机制对增加基因剂量。总的来说，我们的研究结果说明了后基因组杂交早期阶段的抵消机制，填补了现有基因组进化理论中的一个关键空白。

In this project, we aim to understand how neofunctionalization and subfunctionalization occur and whether they are driven by particular genetic elements or functions of nearby genes after genome polyploidization. Following the identification and characterization of genome polyploidization in newly sequenced fungal genomes, we investigated evolution rates among orthologs and paralogs, transcriptional orientation of newly formed adjacent genes, and conservations of stoichiometry for protein complexes and biological pathway components. In this year, we reported the discovery of two recent and independent genome hybridizations within a single clade of a fungal genus, Trichosporon. Comparative genomic analyses revealed that redundant genes are experiencing decelerations, not accelerations, of evolutionary rates. We identified a relationship between gene conversion and decelerated evolution suggesting that gene conversion may improve the genome stability of young hybrids by restricting gene functional divergences. Furthermore, we detected large-scale gene losses from transcriptional and translational machineries that indicate a global compensatory mechanism against increased gene dosages. Overall, our findings illustrate counteracting mechanisms during an early phase of post-genome hybridization and fill a critical gap in existing theories on genome evolution.