Determinants of divergent adaptation and Dobzhansky-Muller interaction in experimental yeast populations.
Divergent adaptation can be associated with reproductive isolation in speciation [1]. We recently demonstrated the link between divergent adaptation and the onset of reproductive isolation in experimental populations of the yeast Saccharomyces cerevisiae evolved from a single progenitor in either a high-salt or a low-glucose environment [2]. Here, whole-genome resequencing and comparative genome hybridization of representatives of three populations revealed 17 mutations, six of which explained the adaptive increases in mitotic fitness. In two populations evolved in high salt, two different mutations occurred in the proton efflux pump gene PMA1 and the global transcriptional repressor gene CYC8; the ENA genes encoding sodium efflux pumps were overexpressed once through expansion of this gene cluster and once because of mutation in the regulator CYC8. In the population from low glucose, one mutation occurred in MDS3, which modulates growth at high pH, and one in MKT1, a global regulator of mRNAs encoding mitochondrial proteins, the latter recapitulating a naturally occurring variant. A Dobzhansky-Muller (DM) incompatibility between the evolved alleles of PMA1 and MKT1 strongly depressed fitness in the low-glucose environment. This DM interaction is the first reported between experimentally evolved alleles of known genes and shows how reproductive isolation can arise rapidly when divergent selection is strong.
Anderson
James B
JB
Centre for the Analysis of Genome Function, Department of Cell and Systems Biology, and Department of Ecology and Evolutionary Biology, University of Toronto, Mississauga, Ontario, Canada.
Funt
Jason
J
Thompson
Dawn Anne
DA
Prabhu
Snehit
S
Socha
Amanda
A
Sirjusingh
Caroline
C
Dettman
Jeremy R
JR
Parreiras
Lucas
L
Guttman
David S
DS
Regev
Aviv
A
Kohn
Linda M
LM
D000220:Adaptation, Biological; D000483:Alleles; D004777:Environment; D049810:Genetic Speciation; D005947:Glucose; D009154:Mutation; D006180:Proton-Translocating ATPases / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D012965:Sodium Chloride
C065455:CYC8 protein, S cerevisiae; C110020:MDS3 protein, S cerevisiae; C092218:MKT1 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D012965:Sodium Chloride; C092477:PMA1 protein, S cerevisiae; D006180:Proton-Translocating ATPases; D005947:Glucose