[Biologist Louis Bernatchez
of Quebec’s Laval University] and his colleagues set out to search for evidence of a different kind of hatchery adaptation, detectable in the epigenome rather than the genome. They trapped juvenile coho salmon (Oncorhynchus kisutch
) just before, or a few weeks after, release from hatcheries on two rivers in British Columbia, and wild juveniles from the same area. Then, they collected and sequenced samples of the fish’s muscle tissue. When they compared the two populations’ genomes, the researchers found no significant genetic differences. But compared to the genomes of their wild counterparts, 100 regions on the genomes of hatchery-reared salmon were differentially methylated, and of those, 89 were hypermethylated.
“That’s a pretty clear-cut and striking result,” Bernatchez says, adding that the results imply “that those genes are downregulated, or less expressed, most likely, in the hatchery fish relative to wild fish.” Some of the hypermethylated regions contain genes for immunity, the transmission of neural signals to muscles for locomotion, and appetite and feeding behaviors. “Quite a few important biological functions were affected,” he adds, indicating that the methylation patterns may play into the fitness differences between wild and hatchery-reared fish.
Editor’s note: Read the full study (behind paywall)
Read full, original post: Study Finds Epigenetic Differences Between Hatchery-Raised and Wild-Born Salmon