Population-specific gene expression responses to hybridization between farm and wild Atlantic salmon
Date
2009-11
Authors
Normandeau, Eric
Hutchings, Jeffrey Alexander
Fraser, Dylan J.
Bernatchez, Louis
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Abstract
Because of intrinsic differences in their genetic architectures, wild populations invaded by
domesticated individuals could experience population-specific consequences following introgression
by genetic material of domesticated origin. Expression levels of 16 000 transcripts were quantified
by microarrays in liver tissue from farm, wild, and farm-wild backcross (i.e. F(1) farm-wild hybrid
x wild; total n = 50) Atlantic salmon (Salmo salar) raised under common environmental conditions.
The wild populations and farm strain originated from three North American rivers in eastern Canada
(Stewiacke, Tusket, and Saint John rivers, respectively). Analysis of variance revealed 177
transcripts with different expression levels among the five strains compared. Five times more of
these transcripts were differentiated between farmed parents and Tusket backcrosses (n = 53) than
between Stewiacke backcrosses and their farmed parents (n = 11). Altered biological processes in
backcrosses also differed between populations both in number and in the type of processes impacted
(metabolism vs immunity). Over-dominant gene expression regulation in backcrosses varied
considerably between populations (23% in Stewiacke vs 44% in Tusket). Hence, the consequences of
introgression of farm genetic material on gene expression depended on population-specific genetic
architectures. These results support the need to evaluate impacts of farm-wild genetic interactions
at the population scale.
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Citation
Normandeau, Eric, Jeffrey A. Hutchings, Dylan J. Fraser, and Louis Bernatchez. 2009. "Population-specific gene expression responses to hybridization between farm and wild Atlantic
salmon." Evolutionary Applications 2(4): 489-503.