Stocking impacts the expression of candidate genes and physiological condition in introgressed brook charr (Salvelinus fontinalis) populations

Abstract

Translocation of plants and animal populations between environments is one of the major forms of anthropogenic perturbation experienced by pristine populations, and consequently, human-mediated hybridization by stocking practices between wild and exogenous conspecifics is of increasing concern. In this study, we compared the expression of seven candidate genes involved in multifactorial traits and regulatory pathways for growth as a function of level of introgressive hybridization between wild and domestic brook charr to test the null hypothesis of no effect of introgression on wild fish. Our analyses revealed that the expression of two of the genes tested, cytochrome c oxidase VIIa and the growth hormone receptor isoform I, was positively correlated with the level of introgression. We also observed a positive relationship between the extent of introgression and physiological status quantified by the Fulton's condition index. The expression of other genes was influenced by other variables, including year of sampling (reflecting different thermal conditions), sampling method and lake of origin. This is the first demonstration in nature that introgression from stocked populations has an impact on the expression of genes playing a role in important biological functions that may be related with fitness in wild introgressed populations.

Investigating genomic and phenotypic parallelism between piscivorous and planktivorous lake trout (Salvelinus namaycush) ecotypes by means ofRADseq and morphometrics analyses

“…; Lamaze et al . ). Therefore, although potential benefits of genetic rescue should not be neglected in such contexts, we suggest that caution should be taken to avoid alteration of local adaptation, in particular adaptation related to the trophic niches.…”

Loss of genetic integrity in wild lake trout populations following stocking: insights from an exhaustive study of 72 lakes from Québec, Canada

“…; Lamaze et al. , ). Even though the extent of local adaptations in lake trout remains largely unknown, stocking could alter local adaptation in wild populations, as shown in other fish species (reviewed in Laikre et al.…”

Strain Specific Genotype−Environment Interactions and Evolutionary Potential for Body Mass in Brook Charr (Salvelinus fontinalis)

“…Whether admixed populations would present an advantage cannot be answered at this stage. However, recent studies on brook charr have shown that selection may favor increased introgression between stocked domestic fish and wild populations at genes involved in important phenotypic traits such as growth and that such introgression also affect levels of gene expression and physiological status, namely condition factor (Lamaze et al 2012a, 2012b). Certainly, further work is needed to highlight how different wild populations could cope with the anticipated climate modifications and how wildlife management practices of wild populations will adjust to these new challenges.…”