A team of researchers from the AMU Faculty of Biology has investigated the effectiveness of so-called ‘genetic rescue’, which involves enriching the gene pools of endangered populations with individuals from outside. Through research conducted using mites, the biologists proved that the benefits of such an approach outweigh its recognised negative effects. The findings, recently published in the prestigious journal Nature Ecology & Evolution, could be of great significance for the practice of saving endangered species.
Human activities are causing environmental changes that lead to declines in various populations and entire species, resulting in negative genetic consequences and potential extinction. These consequences include a loss of genetic diversity, and thus the ability to adapt to a changing environment, as well as a strong influence of random effects (i.e. genetic drift) resulting in the consolidation of harmful mutations, whereas in large populations these would be eliminated by natural selection.
Genetic rescue could prove helpful in such situations, as it can enhance adaptive potential and mask harmful recessive mutations. “The problem is that individuals from outside the population may also carry harmful mutations, or possess gene variants that are poorly compatible with local gene pools; therefore, there has been no consensus among researchers regarding the effectiveness of genetic rescue,” explains Prof. Jacek Radwan from the AMU Faculty of Biology, a co-author of the study.
A team from Adam Mickiewicz University, Poznań, decided to find an answer to the question that preoccupies academics. The researchers also sought to discover how the effectiveness of genetic rescue is influenced by the quality of the ‘rescuers’ – organisms introduced into the population from outside. As Dr Jonathan Parrett from the AMU Faculty of Biology, the NCN project leader and first author of the paper, explains: “It is difficult to conclude by studying a single population; therefore, to increase the strength of our inferences, we used the method of experimental evolution, employing a species of mite with a short life cycle that is perfectly suited to the task and easy to breed. This allowed us to track the genetic rescue effect simultaneously across multiple populations that had been deliberately genetically depleted beforehand,” says Dr Jonathan Parrett. And he adds: “The highly labour-intensive experimental evolution, conducted with the help of Marta Kulczak, MSc, at the Evolutionary Biology Research Unit, lasted two years. We sequenced the genomes of individuals from each experimental population to identify harmful mutations, with the bioinformatics support of Dr Mateusz Konczal from our department."
The research conducted by scientists from the Faculty of Biology at Adam Mickiewicz University, Poznan, has provided a more precise answer to the question of the effectiveness of genetic rescue. “Our research has shown that ‘rescuers’ can, in fact, significantly increase the pool of harmful mutations in the rescued populations. Nevertheless, the effect of masking harmful variants through the influx of fresh genes proved so strong that the overall effect was decidedly beneficial. Crucially, populations subjected to genetic rescue coped significantly better with climate changes simulated in the laboratory. The quality of the rescuer was of minor importance, although males whose good condition was evidenced by the production of costly, thickened legs used for fighting were, in the long run, slightly more effective rescuers," explains Dr Jonathan Parrett. “We believe our findings have significant implications for the practice of saving endangered species, providing a strong argument for the broader use of genetic rescue under the standard condition in such circumstances that the rescuers are not too genetically distant,” adds the scientist.
Link to the article: https://www.nature.com/articles/s41559-026-03080-8
The photo shows the lead author of the paper, Dr Jonathan Parrett. Photo: Karolina Przesmycka
