A migration-associated supergene reveals loss of biocomplexity in Atlantic cod

• Published in: Science Advances
• Main Authors: Kess, Tony, Bentzen, Paul, Lehnert, Sarah J., Sylvester, Emma V.A., Lien, Sigbjorn, Kent, Matthew P., Sinclair-Waters, Marion, Morris, Corey J., Regular, Paul, Fairweather, Robert, Bradbury, Ian R.
• Other Authors: Evolution, Conservation, and Genomics, External Funding
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2019
• Subjects: 1184 Genetics; developmental biology; physiology; EFFECTIVE POPULATION-SIZE; LINKAGE DISEQUILIBRIUM; SELECTIVE SWEEPS; GADUS-MORHUA; R PACKAGE; EVOLUTION; INVERSIONS; DIVERGENCE; SCANS; CONSEQUENCES; atlantic cod; Gadus morhua; Northwest Atlantic
• Online Access: http://hdl.handle.net/10138/304305

Chromosome structural variation may underpin ecologically important intraspecific diversity by reducing recombination within supergenes containing linked, coadapted alleles. Here, we confirm that an ancient chromosomal rearrangement is strongly associated with migratory phenotype and individual genetic structure in Atlantic cod (Gadus morhua) across the Northwest Atlantic. We reconstruct trends in effective population size over the last century and reveal declines in effective population size matching onset of industrialized harvest (after 1950). We find different demographic trajectories between individuals homozygous for the chromosomal rearrangement relative to heterozygous or homozygous individuals for the noninverted haplotype, suggesting different selective histories across the past 150 years. These results illustrate how chromosomal structural diversity can mediate fine-scale genetic, phenotypic, and demographic variation in a highly connected marine species and show how overfishing may have led to loss of biocomplexity within Northern cod stock. Peer reviewed