title: Chromosome number reduction in Eremothecium coryli by two telomere-to-telomere fusions.
abstract: The genus Eremothecium belongs to the Saccharomyces complex of pre-whole-genome duplication (WGD) yeasts and contains both dimorphic and filamentous species. We established the 9.1-Mb draft genome of Eremothecium coryli, which encodes 4,682 genes, 186 tRNA genes, and harbors several Ty3 transposons as well as more than 60 remnants of transposition events (LTRs). The initial de novo assembly resulted in 19 scaffolds, which were assembled based on synteny to other Eremothecium genomes into six chromosomes. Interestingly, we identified eight E. coryli loci that bear centromeres in the closely related species E. cymbalariae. Two of these E. coryli loci, CEN1 and CEN8, however, lack conserved DNA elements and did not convey centromere function in a plasmid stability assay. Correspondingly, using a comparative genomics approach we identified two telomere-to-telomere fusion events in E. coryli as the cause of chromosome number reduction from eight to six chromosomes. Finally, with the genome sequences of E. coryli, E. cymbalariae, and Ashbya gossypii a reconstruction of three complete chromosomes of an Eremothecium ancestor revealed that E. coryli is more syntenic to this ancestor than the other Eremothecium species.
authors.affiliation: Carlsberg Laboratory, Yeast Biology, Copenhagen, Denmark juergen.wendland@carlsberglab.dk.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Wendland
authors.affiliation: Carlsberg Laboratory, Yeast Biology, Copenhagen, Denmark.
authors.forename: Andrea
authors.initials: A
authors.lastname: Walther
mesh_terms: D005075:Biological Evolution; D002503:Centromere / Q000235:genetics; D015825:Chromosomes, Fungal; D004251:DNA Transposable Elements; D055169:Eremothecium / Q000235:genetics*; D016681:Genome, Fungal; D008969:Molecular Sequence Data; D016615:Telomere
chemical_list: D004251:DNA Transposable Elements
keywords: Saccharomyces; ancestral gene order; centromere DNA elements; genome evolution; paleogenomics; synteny; whole-genome sequencing