Hatchery welfare state advocates often argue that hatchery fish are genetically the same as their wild counterparts. Yeah about that.
Biologist Lois Bernatchez 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.
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.
LINK (The Scientist)