| 研究実績の概要 |
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.
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