Is now the time? Review of genetic rescue as a conservation tool for brook trout

Brook trout (Salvelinus fontinalis) is a socioeconomically important fish species for fisheries, aquaculture and aquatic conservation. We produced a 2.5 Gb reference assembly by combining Hi-C chromosome conformation capture with high-coverage short- and long-read sequencing of a fully homozygous mitotic gynogenic doubled haploid fish, which facilitates assembly of highly complex salmonid genomes. The assembly has a N50 of 50.98 Mb and 88.9% of the total assembled sequence length is anchored into 42 main chromosomes, of which 63.44% represents repeated contents, including 1,461,010 DNA transposons. 56,058 genes were found with the NCBI annotation pipeline, with 99% of the 3,640 expected conserved orthologs BUSCO genes (actinopterygii_odb10 lineage database). Additionally, we found significant homology within the 42 chromosomes, as expected for this pseudo-tetraploid species, as well as with the sister species lake trout (Salvelinus namaycush) and Atlantic salmon (Salmo salar). This assembly will serve as a reliable genomic resource for brook trout, thus enabling a wider range of reference-based applications to support ongoing research and management decision-making for the species.

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Sexual selection matters in genetic rescue, but productivity benefits fade over time; a multi-generation experiment to inform conservation

West,

Pointer,

Nash

et al. 2024

Preprint

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Globally, many species are threatened by population decline as a result of anthropogenic changes. Smaller populations are at greater risk of fragmentation, genetic isolation, and eventual inbreeding depression. As genetic load is expressed and adaptive potential is lost, risk of population extinction greatly increases. Genetic rescue, the controlled introduction of genetic variation, is a method used to potentially relieve such effects in small populations. However, without understanding how the characteristics of rescuers impact rescue attempts, in both the short- and long-term, interventions run the risk of being sub-optimal, or even counterproductive. Here, we use the Red Flour Beetle (Tribolium castaneum) to experimentally test the impact of rescuer sex, and sexual selection background, on population productivity. We record the impact of genetic rescue on population productivity in 24/36 replicated populations for ten generations following intervention. We find little or no impact of rescuer sex on the efficacy of rescue (P = 0.926) but show that a background of elevated sexual selection makes individuals more effective rescuers (P = 0.024). Importantly, in both experiments, rescue effects on productivity diminish 6-10 generations after the rescue event. Our results confirm that the efficacy of genetic rescue can be influenced by characteristics of the rescuers and, for the first time, that the level of sexual selection in the rescuing population is an important factor. We show that any increase in fitness associated with rescue may only last for a limited number of generations, suggesting implications for conservation policy and practice.

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Is now the time? Review of genetic rescue as a conservation tool for brook trout

Cited by 4 publications

References 73 publications

Genetic structure of restored Brook Trout populations in the Southern Appalachian Mountains indicates successful reintroductions

Genetic structure of restored Brook Trout populations in the Southern Appalachian Mountains indicates successful reintroductions

Chromosome-level genome assembly of a doubled haploid brook trout (Salvelinus fontinalis)

Sexual selection matters in genetic rescue, but productivity benefits fade over time; a multi-generation experiment to inform conservation

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