title: Global deceleration of gene evolution following recent genome hybridizations in fungi.
abstract: Polyploidization events such as whole-genome duplication and inter-species hybridization are major evolutionary forces that shape genomes. Although long-term effects of polyploidization have been well-characterized, early molecular evolutionary consequences of polyploidization remain largely unexplored. Here, we report 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.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan;
authors.forename: Sira
authors.initials: S
authors.lastname: Sriswasdi
authors.affiliation: Japan Collection of Microorganisms, RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan;
authors.forename: Masako
authors.initials: M
authors.lastname: Takashima
authors.affiliation: Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama, Kanagawa 230-0045, Japan;
authors.forename: Ri-Ichiroh
authors.initials: R
authors.lastname: Manabe
authors.affiliation: Japan Collection of Microorganisms, RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan;
authors.forename: Moriya
authors.initials: M
authors.lastname: Ohkuma
authors.affiliation: Department of Microbiology, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588, Japan;
authors.forename: Takashi
authors.initials: T
authors.lastname: Sugita
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8568, Japan; Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Iwasaki
mesh_terms: D003654:Deceleration; D019143:Evolution, Molecular; D005785:Gene Conversion; D016681:Genome, Fungal / Q000235:genetics*; D006824:Hybridization, Genetic; D010802:Phylogeny; D011123:Polyploidy; D014250:Trichosporon / Q000235:genetics*