Similar Mutation Rates but Highly Diverse Mutation Spectra in Ascomycete and Basidiomycete Yeasts
Abstract
Yeast species are extremely diverse and not monophyletic. Because the majority of yeast research focuses on ascomycetes, the mutational determinants of genetic diversity across yeast species are not well understood. By combining mutation-accumulation techniques with whole-genome sequencing, we resolved the genomic mutation rate and spectrum of the oleaginous (oil-producing)red yeast Rhodotorula toruloides, the first such study in the fungal phylum Basidiomycota. We find that the mutation spectrum is quite different from what has been observed in all other studied unicellular eukaryotes, but similar to that in most bacteria predominance of transitions relative to transversions. Rhodotorula toruloides has a significantly higher A:T!G:C transition rate possibly elevated by the abundant flanking G/C nucleotides in the GC-rich genome, as well as a much lower G:C!T:A transversionrate. In spite of these striking differences, there are substantial consistencies between R. toruloides and the ascomycete model yeasts: a spontaneous base-substitution mutation rate of 1.9010 10 per site per cell division as well as an elevated mutation rate at nonmethylated5CpG3 sites. These results imply the evolution of variable mutation spectra in the face of similar mutation rates in yeasts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 24, 2016
- Accession Number
- AD1053432
Entities
People
- Emily Williams
- Hongan Long
- Megan G. Behringer
- Michael Lynch
- Ronald Te
Organizations
- Indiana University