Dilan Saatoglu

and 7 more

Dispersal affects evolutionary processes by changing population sizes and their genetic composition, influencing the viability and persistence of populations. Investigating which mechanisms underlie variation in dispersal phenotypes and whether populations harbor adaptive potential for dispersal is crucial to understanding the eco-evolutionary dynamics of this important trait. Here, we investigate the genetic architecture of dispersal in an insular metapopulation of house sparrows. We use an extensive long-term individual-based ecological dataset and high-density single nucleotide polymorphism (SNP) genotypes for over 2500 individuals. We conducted a genome-wide association study (GWAS), finding a relationship between dispersal probability and a SNP located near genes known to regulate circadian rhythmic, glycogenesis and exercise performance, among other functions. However, this SNP only explained 3.8% of variance, suggesting that dispersal is a polygenic trait. We then used an animal model to estimate heritable genetic variation (Va), which composes 10% of the total overall variation in dispersal probability. Finally, we investigated differences in Va across populations occupying ecologically relevant habitat types (farm vs. non-farm) using a genetic-groups animal model. We found higher mean breeding value, Va, and heritability for the farm habitat, suggesting different adaptive potentials across habitats. Moreover, dispersal phenotypes may depend on genotype-by-environment interactions. Our results suggest a complex genetic architecture of dispersal, and demonstrate that adaptive potential may be environment-dependent in key eco-evolutionary traits. The eco-evolutionary implications of such environment-dependence and consequent spatial variation are likely to be ever more important with the increased fragmentation and loss of suitable habitats for many natural populations.

Debora Goedert

and 2 more

Natural dispersal between populations, and resulting immigration, influences population size and genetic diversity and is therefore a key process driving reciprocal interactions between ecological and evolutionary dynamics. Both ecological and evolutionary consequences of dispersal fundamentally depend on the relative fitnesses of immigrants and their various descendants manifested in the context of natural environments. Yet, despite this commonality, recent research advances in predicting immigrants' legacies remain substantially disconnected across disciplines. To bridge resulting divides, we synthesize empirical and theoretical work examining fitness consequences of inter-breeding across the full spectrum of genetic divergence from inbred lines to inter-specific hybridization. We demonstrate how common underlying processes can generate positive or negative fitness consequences of immigration depending on interacting genetic and environmental effects. Impacts of inter-breeding following natural dispersal among sub-populations could consequently vary dramatically, shaping eco-evolutionary outcomes. Yet, our systematic literature review reveals a striking paucity of empirical studies that quantify multi-generational fitness consequences of immigration in natural metapopulations, precluding general inferences on outcomes. Hence, to provide new impetus, we highlight key theoretical and empirical gaps, and outline how cutting-edge statistical and genomic tools could be combined with multi-generational field datasets to advance understanding of dispersal-mediated drivers and constraints on eco-evolutionary dynamics.