Polyploidy can drive rapid adaptation in yeast.

• Autores: Anna Selmecki, Yosef E. Maruvka, Phillip A. Richmond, Marie Guillet, Noam Shoresh, Amber L. Sorenson
• Localización: Nature: International weekly journal of science, ISSN 0028-0836, Vol. 519, Nº 7543, 2015, págs. 349-352
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Polyploidy is observed across the tree of life, yet its influence on evolution remains incompletely understood 1,2,3,4. Polyploidy, usually whole-genome duplication, is proposed to alter the rate of evolutionary adaptation. This could occur through complex effects on the frequency or fitness of beneficial mutations 2,5,6,7. For example, in diverse cell types and organisms, immediately after a whole-genome duplication, newly formed polyploids missegregate chromosomes and undergo genetic instability 8,9,10,11,12,13. The instability following whole-genome duplications is thought to provide adaptive mutations in microorganisms 13,14 and can promote tumorigenesis in mammalian cells 11,15. Polyploidy may also affect adaptation independently of beneficial mutations through ploidy-specific changes in cell physiology 16. Here we perform in vitro evolution experiments to test directly whether polyploidy can accelerate evolutionary adaptation. Compared with haploids and diploids, tetraploids undergo significantly faster adaptation. Mathematical modelling suggests that rapid adaptation of tetraploids is driven by higher rates of beneficial mutations with stronger fitness effects, which is supported by whole-genome sequencing and phenotypic analyses of evolved clones. Chromosome aneuploidy, concerted chromosome loss, and point mutations all provide large fitness gains. We identify several mutations whose beneficial effects are manifest specifically in the tetraploid strains. Together, these results provide direct quantitative evidence that in some environments polyploidy can accelerate evolutionary adaptation.