Diverse mating phenotypes impact the spread of wtf meiotic drivers in Schizosaccharomyces pombe
Authors: Jose Fabricio López Hernández 1; Rachel M. Helston 1; Jeffrey J. Lange 1; R. Blake Billmyre 1; Samantha H. Schaffner 2; Michael T. Eickbush 1; Scott McCroskey 1; Sarah E. Zanders 1,3
Affiliations: 1) Stowers Institute for Medical Research, Kansas City, MO 64110, USA.; 2) Kenyon College, Gambier, OH 43022, USA.; 3) Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Keywords: Experimental evolution
Meiotic drivers are genetic elements that break Mendel’s law of segregation to be transmitted into more than half of the offspring produced by a heterozygote. The success of a driver relies on outcrossing because drivers gain their advantage in heterozygotes. It is therefore curious that Schizosaccharomyces pombe, a species reported to rarely outcross, harbors many meiotic drivers. To address this paradox, we measured mating phenotypes in S. pombe natural isolates.
We found that the propensity to inbreed varies between natural isolates and can be affected both by cell density and by the available sexual partners. Additionally, using experimental evolution approaches and theoretical modeling, we found that the observed level of inbreeding slows, but does not prevent, the spread of a wtf meiotic driver in the absence of additional fitness costs. These analyses reveal parameters critical to understanding the evolution of S. pombe and help explain the success of meiotic drivers in this species.