Stabilizing selection on Atlantic cod supergenes through a millennium of extensive exploitation

Area of Science:

• Ecology
• Evolutionary Biology
• Genomics

Background:

• Life on Earth experiences cycles of ecological stasis and disruption, influenced by geological and climatic changes.
• Human activities are increasingly causing ecological disruption, leading to the proposed era of the Anthropocene.
• Understanding ecological stasis drivers is crucial for intervention and mitigation strategies, especially given ongoing mass extinctions.

Purpose of the Study:

• To investigate the genetic basis of ecological stasis in the Atlantic cod (Gadus morhua).
• To link genetic factors to species persistence and ecosystem stability.
• To infer historical population dynamics and their relationship to human impact.

Main Methods:

• Whole-genome resequencing of Atlantic cod (Gadus morhua).
• Analysis of stabilizing selection acting on specific genetic regions.
• Genomic inference of historical effective population sizes.

Main Results:

• Identification of three extensive "supergenes" in Atlantic cod maintained by stabilizing selection.
• These supergenes are linked to species persistence and ecological stasis.
• Genomic data indicate a continuous decline in North Sea-Skagerrak-Kattegat cod populations over millennia, suggesting early marine Anthropocene impacts.

Conclusions:

• Stabilizing selection on specific supergenes contributes to the ecological stasis of Atlantic cod.
• The Atlantic cod's population decline suggests a long history of human-induced stress, potentially marking an early marine Anthropocene.
• Understanding these genetic mechanisms is vital for conserving keystone species and ecosystem stability.