Abstract
Earth’s temperature is increasing due to anthropogenic CO2 emissions; and organisms need either to adapt to higher temperatures, migrate into colder areas, or face extinction. Temperature affects nearly all aspects of an organism’s physiology via its influence on metabolic rate and protein structure, therefore genetic adaptation to increased temperature may be much harder to achieve compared to other abiotic stresses. There is still much to be learned about the evolutionary potential for adaptation to higher temperatures, therefore we studied the quantitative genetics of growth rates in different temperatures that make up the thermal performance curve of the fungal model system Neurospora crassa. We studied the amount of genetic variation for thermal performance curves and examined possible genetic constraints by estimating the G-matrix. We observed a substantial amount of genetic variation for growth in different temperatures, and most genetic variation was for performance curve elevation. Contrary to common theoretical assumptions, we did not find strong evidence for genetic trade-offs for growth between hotter and colder temperatures. We also simulated short term evolution of thermal performance curves of N. crassa, and suggest that they can have versatile responses to selection.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Data accessibility statement The data and analysis scripts will be deposited to Data dryad upon acceptance.
We have revised the manuscript following reviewers comments. Biggest changes are that we know use the evolvability statistics of Hansen & Hoyle to evaluate trait autonomy, and how easy it is to evolve along the simulated selection gradients. The simulation part of the manuscript has been extensively revised and figures relating to these results have been redrawn. A better explanation of the biological interpretation of selection and gradient and selection differentials has been added. Furthermore, numerous fixes and clarifications have been done.