Abstract Detail

Population Genetics/Genomics

So, Cameron [1], Weis, Arthur [1], Shaw, Ruth [2], Shaw, Frank [3], Rotman, Sydney [1], Sibolibane, Micha [1].

The adaptive potential of lifetime fitness increases under a future climate change scenario in a population of Brassica rapa.

The persistence of any declining population in the face of some environmental perturbation may depend on how fast natural selection restores fitness, a process called “evolutionary rescue”. Despite many studies reporting the potential for fitness-related traits to evolve under some selection gradient, little is known regarding the capacity for fitness itself to undergo rapid adaptive evolution. This is especially true for populations experiencing or bound to experience deleterious and novel effects of contemporary climate change. Fundamental theory shows that evolutionary rescue depends upon the ratio of a population’s additive genetic variance of fitness (VA(W)) to the mean fitness (W). Expression of VA(W) depends on the environment to which the population is exposed. I conducted an outdoor warming experiment to estimate the change in VA(W) and  in a population of the annual field mustard Brassica rapa using temperature regimes predicted in the year 2100 (IPCC RCP8.5 AR5). With an extended family crossing design (including siblings and first cousins) combined with aster models and commonly used “animal” models under a Bayesian quantitative genetic framework, I estimated the additive genetic variance of lifetime fitness and fitness-related traits, in addition to dominance genetic variance and maternal effects for ftness component traits. Surprisingly, plants exposed to a warmer climate exhibited greater , suggesting plasticity may play a key role in plant evolutionary responses to contemporary climate change, but could also hinder the potential to adapt through the ratio of VA(W) to W. Nevertheless, the magnitude of VA(W) expressed in heated conditions was considerably higher, thereby a greater capacity to adapt was observed under heated conditions. My findings suggest that standing genetic variation in the annual B. rapa may be sufficient to buffer and facilitate rapid adaptive evolution to new temperature regimes imposed by contemporary climate change.

1 - University of Toronto, Ecology & Evolutionary Biology, 25 Willcocks Street, Toronto, ON, M5S3B2, Canada
2 - University Of Minnesota, Department Of Ecology, Evolution And Behavior, 1479 Gortner Ave, 140 Gortner, St. Paul, MN, 55108, United States
3 - St. Paul, MN, USA

climate change
genetic variance
lifetime fitness
quantitative genetics.

Presentation Type: Oral Paper
Session: POPGEN1, Population Genetics/Genomics I
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 4:15 PM
Number: POPGEN1006
Abstract ID:725
Candidate for Awards:Margaret Menzel Award

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