INTROSYM · Conservation impacts of hybridization and introgression in symbionts: Measuring the magnitude and role in shaping eco-evolutionary variables

Conservation impacts of hybridization and introgression in symbionts: Measuring the magnitude and role in shaping eco-evolutionary variables

Hybridization is becoming increasingly acknowledged as a process that has played (and often still plays) a major role in the Ecology and Evolution of many taxa. However, most studies of hybridization have been carried out in model taxa, such that much of the diversity of eco-evolutionary histories (e.g. coevolving species) and the potentially key role that hybridization plays across a variety of groups remain unstudied. Symbionts (i.e. parasites, mutualists, and commensals that intimately interact with their hosts) comprise the most diverse group of organisms in the world. Symbionts are essential to ecosystems, comprising up to 75% of all ecological interactions. A major concern is that conservative estimates predict that up to 10% of symbiont species are expected to go extinct by 2070 due to climate change. In some cases, climate change causes species to change their distributions such that they overlap with other species with which they can hybridize. A dominant species may even hybridize a less dominant species into extinction. Despite their diversity, relevance, and conservation status, primary aspects of the Ecology, Evolution, and Conservation Biology of symbionts are yet to be understood, especially when compared to what is known about free-living organisms. This lack of knowledge is particularly acute when it comes to understanding the role of hybridization among symbiont taxa. The overall purpose of this project was to follow an integrative approach to disentangle how hybridization operates in symbionts, a group of taxa exhibiting unique eco-evolutionary trajectories, and for which hybridization has almost never been studied. The main objective of this project was to disentangle how hybridization operates in symbionts. To achieve this, we leveraged already generated high coverage (>50X) whole-genome data of feather lice from at least 600 louse individuals belonging to around 500 species and 140 genera. This sampling represented around 90% of feather louse genera, and most host families. Conclusions: Over the course of the project, we found that introgression is highly prevalent across all studied clades, hinting at its significance in symbiont evolution. Notably, we discovered patterns suggesting that hybridization might provide essential genetic material for colonizing new host species. The project's findings pave the way for deeper insights into symbiont evolution and provide crucial knowledge for conservation efforts.

Data: CORDIS, © European Union