Different selective pressures lead to different genomic outcomes as newly-formed hybrid yeasts evolve
Open Access
- 2 April 2012
- journal article
- Published by Springer Science and Business Media LLC in BMC Evolutionary Biology
- Vol. 12 (1), 46
- https://doi.org/10.1186/1471-2148-12-46
Abstract
Interspecific hybridization occurs in every eukaryotic kingdom. While hybrid progeny are frequently at a selective disadvantage, in some instances their increased genome size and complexity may result in greater stress resistance than their ancestors, which can be adaptively advantageous at the edges of their ancestors' ranges. While this phenomenon has been repeatedly documented in the field, the response of hybrid populations to long-term selection has not often been explored in the lab. To fill this knowledge gap we crossed the two most distantly related members of the Saccharomyces sensu stricto group, S. cerevisiae and S. uvarum, and established a mixed population of homoploid and aneuploid hybrids to study how different types of selection impact hybrid genome structure. As temperature was raised incrementally from 31°C to 46.5°C over 500 generations of continuous culture, selection favored loss of the S. uvarum genome, although the kinetics of genome loss differed among independent replicates. Temperature-selected isolates exhibited greater inherent and induced thermal tolerance than parental species and founding hybrids, and also exhibited ethanol resistance. In contrast, as exogenous ethanol was increased from 0% to 14% over 500 generations of continuous culture, selection favored euploid S. cerevisiae x S. uvarum hybrids. Ethanol-selected isolates were more ethanol tolerant than S. uvarum and one of the founding hybrids, but did not exhibit resistance to temperature stress. Relative to parental and founding hybrids, temperature-selected strains showed heritable differences in cell wall structure in the forms of increased resistance to zymolyase digestion and Micafungin, which targets cell wall biosynthesis. This is the first study to show experimentally that the genomic fate of newly-formed interspecific hybrids depends on the type of selection they encounter during the course of evolution, underscoring the importance of the ecological theatre in determining the outcome of the evolutionary play.Keywords
This publication has 74 references indexed in Scilit:
- Microbe domestication and the identification of the wild genetic stock of lager-brewing yeastProceedings of the National Academy of Sciences of the United States of America, 2011
- GENETIC DISTANCE BETWEEN SPECIES PREDICTS NOVEL TRAIT EXPRESSION IN THEIR HYBRIDSEvolution, 2009
- Reconstruction of the genome origins and evolution of the hybrid lager yeast Saccharomyces pastorianusGenome Research, 2008
- Stress and domestication traits increase the relative fitness of crop–wild hybrids in sunflowerEcology Letters, 2007
- Isolation of quiescent and nonquiescent cells from yeast stationary-phase culturesThe Journal of cell biology, 2006
- Genome evolution in yeastsNature, 2004
- Sequencing and comparison of yeast species to identify genes and regulatory elementsNature, 2003
- Dissecting the architecture of a quantitative trait locus in yeastNature, 2002
- The heat shock and ethanol stress responses of yeast exhibit extensive similarity and functional overlapFEMS Microbiology Letters, 1995
- Long-Term Experimental Evolution in Escherichia coli. I. Adaptation and Divergence During 2,000 GenerationsThe American Naturalist, 1991