My first preprint and first paper on fungi genomics, mating-type chromosomes and differential gene expression
02/05/19 23:56 Category: Papers
Differential gene expression is associated with degeneration of mating-type chromosomes in the absence of sexual antagonism
Figure1. Comparisons of differentially expressed (DE) versus non-differentially expressed (non-DE) genes between mating types of Microbotryum lychnidis-dioicae for various degeneration-associated traits within genomic compartments.
Figure2. Significant predictors of the degree of differential expression between mating types of Microbotryum lychnidis-dioicae testing directional effects of degeneration-associated traits.
Figure1. Comparisons of differentially expressed (DE) versus non-differentially expressed (non-DE) genes between mating types of Microbotryum lychnidis-dioicae for various degeneration-associated traits within genomic compartments.
Figure2. Significant predictors of the degree of differential expression between mating types of Microbotryum lychnidis-dioicae testing directional effects of degeneration-associated traits.
Differential gene expression is associated with degeneration of mating-type chromosomes in the absence of sexual antagonism
Across kingdoms, a dominant view is DE genes on sex chr. results from sexually antagon. selection on male vs. female traits. However, the compelling logic of SA selection hasn’t been met with strong empirical evidence, alternative causes haven’t been well considered/evaluated. We tested the hypothesis that degenerative mutations, which also characterize sex chr. evolution, are responsible for differential gene expression. We did so using a model system where sexual antagonism does not occur as a confounding factor (i.e. the isogamous fungus).
Our genomic and gene expression analyses reveal that DE between haploid fungal mating types were enriched only on the old regions of the mating-type chromosomes with most ancient recombination suppression, associated with multiple signatures of sequence degeneration, including dN substitution rates, indels and premature stop codons, transposable element insertions, altered intron & GC content. The findings strongly indicate degen. mutations are important in the evolution of DE expression in non-recombining regions on mating-type/sex chromosomes.
We show that DE should not be taken as necessarily arising from antagonistic selection, and that mutations with degenerative effects must to be considered wherever reproductive compatibility or sex is determined by genes located in regions of recombination suppression.
Across kingdoms, a dominant view is DE genes on sex chr. results from sexually antagon. selection on male vs. female traits. However, the compelling logic of SA selection hasn’t been met with strong empirical evidence, alternative causes haven’t been well considered/evaluated. We tested the hypothesis that degenerative mutations, which also characterize sex chr. evolution, are responsible for differential gene expression. We did so using a model system where sexual antagonism does not occur as a confounding factor (i.e. the isogamous fungus).
Our genomic and gene expression analyses reveal that DE between haploid fungal mating types were enriched only on the old regions of the mating-type chromosomes with most ancient recombination suppression, associated with multiple signatures of sequence degeneration, including dN substitution rates, indels and premature stop codons, transposable element insertions, altered intron & GC content. The findings strongly indicate degen. mutations are important in the evolution of DE expression in non-recombining regions on mating-type/sex chromosomes.
We show that DE should not be taken as necessarily arising from antagonistic selection, and that mutations with degenerative effects must to be considered wherever reproductive compatibility or sex is determined by genes located in regions of recombination suppression.