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

Fabien C Lamaze,Dany Garant,Louis Bernatchez

doi:10.1111/eva.12022

Fabien C Lamaze, Dany Garant + Show 1 more

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https://doi.org/10.1111/eva.12022

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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.

Highlights

Translocation of plants and animal populations between environments is one of the major forms of anthropogenic perturbation experienced by pristine populations (Suarez and Tsutsui 2008; Laikre et al 2010), which often result in hybridization between native and exogenous individuals (Allendorf et al 2001; Randi 2008)
Three populations significantly deviated from Hardy– Weinberg equilibrium: namely Methot Lake (MET), JC and Lac des Ecorces aquaculture facility (LDE) (Table S3)
The main objective of this study was to assess the impacts of domestic introgression on the expression profile of seven candidate genes in two stocked brook charr populations in natural conditions

Summary

Introduction

Translocation of plants and animal populations between environments is one of the major forms of anthropogenic perturbation experienced by pristine populations (Suarez and Tsutsui 2008; Laikre et al 2010), which often result in hybridization between native and exogenous individuals (Allendorf et al 2001; Randi 2008). Effects of hybridization can be harmful (Rhymer and Simberloff 1996; Allendorf et al 2001; Laikre et al 2010), and as a consequence, human-mediated hybridization by stocking practices, between individuals from wild populations and their exogenous conspecifics, is of increasing concern (Allendorf et al 2001; Edmands 2007; Randi 2008). The process of domestication can be perceived as fast human-induced evolution leading to rapid changes in the genetic architecture, which is the sum of genetic interactions responsible for the development of characters in strains under selection (Burger et al 2008)

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