Aneuploidy underlies rapid adaptive evolution of yeast cells deprived of a conserved cytokinesis motor.
The ability to evolve is a fundamental feature of biological systems, but the mechanisms underlying this capacity and the evolutionary dynamics of conserved core processes remain elusive. We show that yeast cells deleted of MYO1, encoding the only myosin II normally required for cytokinesis, rapidly evolved divergent pathways to restore growth and cytokinesis. The evolved cytokinesis phenotypes correlated with specific changes in the transcriptome. Polyploidy and aneuploidy were common genetic alterations in the best evolved strains, and aneuploidy could account for gene expression changes due directly to altered chromosome stoichiometry as well as to downstream effects. The phenotypic effect of aneuploidy could be recapitulated with increased copy numbers of specific regulatory genes in myo1Delta cells. These results demonstrate the evolvability of even a well-conserved process and suggest that changes in chromosome stoichiometry provide a source of heritable variation driving the emergence of adaptive phenotypes when the cell division machinery is strongly perturbed.
Rancati
Giulia
G
Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA.
Pavelka
Norman
N
Fleharty
Brian
B
Noll
Aaron
A
Trimble
Rhonda
R
Walton
Kendra
K
Perera
Anoja
A
Staehling-Hampton
Karen
K
Seidel
Chris W
CW
Li
Rong
R
D000782:Aneuploidy; D048749:Cytokinesis; D019020:Directed Molecular Evolution; D017353:Gene Deletion; D016681:Genome, Fungal; D018995:Myosin Heavy Chains / Q000235:genetics*; D011123:Polyploidy; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*
C112936:MYO1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D018995:Myosin Heavy Chains