Natural environments are being transformed at an ever faster rate, owing to ongoing climate change. This finding exacerbates the challenges for the many species already at risk from habitat loss.
“Because mutations are on the whole detrimental to fitness, higher temperatures are expected to increase extinction risk in a warmer climate for many species, particularly those with small and fragmented populations. This research underscores the urgency with which we must preserve habitat and its connectivity to maintain gene-flow.
While higher temperatures can also amplify the positive effects of beneficial mutations the species that are most likely to benefit will be those that already have large populations and a high reproductive rate. These are more likely to be pests, which could further increase the extinction risk for rarer species”, says Richard Walters, researcher at Centre for Environmental and Climate Science (CEC) at Lund University.
In the study, which is a collaboration between researchers at Lund University and Uppsala University, theoretical models of how proteins function were combined with results from experiments comparing the effects of mutations across different forms of life in various habitats. The researchers experimented on beetles carrying new mutations, but also analysed results from previous, similar studies examining both unicellular microorganisms, such as yeasts, bacteria and viruses, and multicellular life forms such as thale cress (Arabidopsis thaliana), fruit fly (Drosophila melanogaster) and roundworm (Caenorhabditis elegans).
By combining all this information, the researchers were able to clarify how the organisms fared in various environments before and after the mutations were produced. Above all, the aim was to find out whether environmental conditions that imposed some kind of stress on the individual caused the mutations’ detrimental effects to be expressed more or less. They manipulated the temperature to find out what effect this had.
“Individuals with and without mutations suffered just as much from the stressful environment. But when we looked at the studies where temperatures had been manipulated we found that, with higher temperatures, the effects in individuals carrying new mutations were worse than in those that lacked them,” says David Berger at Uppsala University’s Department of Ecology and Genetics.
The study indicates that if calculations by the Intergovernmental Panel on Climate Change (IPCC) of global warming by 2–4°C in the century ahead become a reality, the result may be a doubling of the harmful effects of new mutations in tropical species.
“Since mutations are inherited and also arise in every new generation, a marked increase in their damaging effects would have major implications both for organisms’ adaptability and for the types of adaptations we can expect to see in them if global temperatures keep rising. Our results may therefore be important for understanding how future global warming may affect biodiversity,” Berger says.
Berger D, Stångberg J, Baur J, Walters RJ. (2021) Elevated temperature increases genome-wide selection on de novo mutations. Proceedings of the Royal Society B 20203094.
Elevated temperature increases genome-wide selection on de novo mutations - article at royalsocietypublishing.org