Abstract
AbstractFission yeasts are an ancient group of fungal species that diverged from each other from tens to hundreds of million years ago. Among them is the preeminent model organismSchizosaccharomyces pombe, which has significantly contributed to our understandings of molecular mechanisms underlying fundamental cellular processes. The availability of the genomes ofS. pombeand three other fission yeast speciesS. japonicus,S. octosporus, andS. cryophilushas enabled cross-species comparisons that provide insights into the evolution of genes, pathways, and genomes. Here, we performed genome sequencing on the type strain of the recently identified fission yeast speciesS. osmophilusand obtained a complete mitochondrial genome and a nuclear genome assembly with gaps only at rRNA gene arrays. A total of 5098 protein-coding nuclear genes were annotated and orthologs for more than 95% of them were identified. Genome-based phylogenetic analysis showed thatS. osmophilusis most closely related toS. octosporusand these two species diverged around 16 million years ago. To demonstrate the utility of thisS. osmophilusreference genome, we conducted cross-species comparative analyses of centromeres, telomeres, transposons, the mating-type region, Cbp1 family proteins, and mitochondrial genomes. These analyses revealed conservation of repeat arrangements and sequence motifs in centromere cores, identified telomeric sequences composed of two types of repeats, delineated relationships among Tf1/sushi group retrotransposons, characterized the evolutionary origins and trajectories of Cbp1 family domesticated transposases, and discovered signs of interspecific transfer of two types of mitochondrial selfish elements.
Publisher
Cold Spring Harbor Laboratory