Multigenerational hybridisation and its consequences for maternal effects in Atlantic salmon

Area of Science:

• Evolutionary biology
• Genetics
• Animal breeding

Background:

• Outbreeding between populations impacts evolution, conservation, and agriculture.
• Maternal effects significantly influence early offspring survival.
• Fitness consequences of outbreeding are known, but maternal influence remains understudied in wild populations.

Purpose of the Study:

• Investigate how outbreeding affects maternal effects in Atlantic salmon (Salmo salar).
• Analyze multigenerational crosses between wild and domesticated populations.
• Examine traits during the yolk-feeding stage in hybrid offspring.

Main Methods:

• Utilized cross-means analysis in a common laboratory environment.
• Studied traits in up to third-generation hybrid Atlantic salmon.
• Quantified residual yolk mass and offspring size relative to total mass.

Main Results:

• Maternal additive outbreeding effects influenced most offspring traits.
• Yolk mass was also influenced by maternal dominant effects.
• First-generation hybrid offspring showed excessive residual yolk mass (23-97% greater).
• Offspring genetics (additive, epistatic) modified maternal effects, increasing size with domesticated alleles.

Conclusions:

• Disruption of co-adapted maternal genetic control by combining divergent alleles.
• Complex maternal and offspring outbreeding effects complicate hybrid phenotype prediction.
• Further research needed to understand fitness implications and phenotype-by-environment interactions.