TY - JOUR

T1 - Epistatic regulation of growth in Atlantic salmon revealed: a QTL study performed on the domesticated-wild interface

AU - Besnier, Francois

AU - Solberg, Monica Favnebøe

AU - Harvey, Alison

AU - Carvalho, Gary

AU - Bekkevold, Dorte

AU - Taylor, Martin I.

AU - Creer, Simon

AU - Nielsen, Einar E.

AU - Skaala, Oystein

AU - Ayllon, Fernando

AU - Dahle, Geir

AU - Glover, Kevin Alan

PY - 2020/2/7

Y1 - 2020/2/7

N2 - BackgroundQuantitative traits are typically considered to be under additive genetic control. Although there are indications that non-additive factors have the potential to contribute to trait variation, experimental demonstration remains scarce. Here, we investigated the genetic basis of growth in Atlantic salmon by exploiting the high level of genetic diversity and trait expression among domesticated, hybrid and wild populations.ResultsAfter rearing fish in common-garden experiments under aquaculture conditions, we performed a variance component analysis in four mapping populations totaling ~ 7000 individuals from six wild, two domesticated and three F1 wild/domesticated hybrid strains. Across the four independent datasets, genome-wide significant quantitative trait loci (QTLs) associated with weight and length were detected on a total of 18 chromosomes, reflecting the polygenic nature of growth. Significant QTLs correlated with both length and weight were detected on chromosomes 2, 6 and 9 in multiple datasets. Significantly, epistatic QTLs were detected in all datasets.DiscussionThe observed interactions demonstrated that the phenotypic effect of inheriting an allele deviated between half-sib families. Gene-by-gene interactions were also suggested, where the combined effect of two loci resulted in a genetic effect upon phenotypic variance, while no genetic effect was detected when the two loci were considered separately. To our knowledge, this is the first documentation of epistasis in a quantitative trait in Atlantic salmon. These novel results are of relevance for breeding programs, and for predicting the evolutionary consequences of domestication-introgression in wild populations.

AB - BackgroundQuantitative traits are typically considered to be under additive genetic control. Although there are indications that non-additive factors have the potential to contribute to trait variation, experimental demonstration remains scarce. Here, we investigated the genetic basis of growth in Atlantic salmon by exploiting the high level of genetic diversity and trait expression among domesticated, hybrid and wild populations.ResultsAfter rearing fish in common-garden experiments under aquaculture conditions, we performed a variance component analysis in four mapping populations totaling ~ 7000 individuals from six wild, two domesticated and three F1 wild/domesticated hybrid strains. Across the four independent datasets, genome-wide significant quantitative trait loci (QTLs) associated with weight and length were detected on a total of 18 chromosomes, reflecting the polygenic nature of growth. Significant QTLs correlated with both length and weight were detected on chromosomes 2, 6 and 9 in multiple datasets. Significantly, epistatic QTLs were detected in all datasets.DiscussionThe observed interactions demonstrated that the phenotypic effect of inheriting an allele deviated between half-sib families. Gene-by-gene interactions were also suggested, where the combined effect of two loci resulted in a genetic effect upon phenotypic variance, while no genetic effect was detected when the two loci were considered separately. To our knowledge, this is the first documentation of epistasis in a quantitative trait in Atlantic salmon. These novel results are of relevance for breeding programs, and for predicting the evolutionary consequences of domestication-introgression in wild populations.

KW - Growth

KW - Hybrid

KW - Inheritance

KW - Introgression

KW - Linkage mapping

KW - Non-additive

U2 - 10.1186/s12863-020-0816-y

DO - 10.1186/s12863-020-0816-y

M3 - Article

C2 - 32033538

VL - 21

JO - BMC Genetics

JF - BMC Genetics

SN - 1471-2156

IS - 1

M1 - 13

ER -