Data from: Evolutionary rescue of sexual and asexual populations in a deteriorating environment

The environmental change experienced by many contemporary populations of
organisms poses a serious risk to their survival. From the theory of
evolutionary rescue we predict that the combination of sex and genetic
diversity should increase the probability of survival by increasing
variation and thereby the probability of generating a type that can
tolerate the stressful environment. We tested this prediction by comparing
experimental populations of Chlamydomonas reinhardtii that differ in
sexuality and in the initial amount of genetic diversity. The lines were
serially propagated in an environment where the level of stress caused by
salt increased over time from fresh water to the limits of marine
conditions. In the long term, the combination of high diversity and
obligate sexuality was most effective in supporting evolutionary rescue.
Most of the adaptation to high-salt environments in the obligate
sexual-high diversity lines had occurred by mid-way through the
experiment, indicating that positive genetic correlations of adaptation to
lethal stress with adaptation to sublethal stress greatly increased the
probability of evolutionary rescue. The evolutionary rescue events
observed in this study provide evidence that major shifts in ways of life
can arise within short time frames through the action of natural selection
in sexual populations.