Study Finds Rapid DNA Changes In Hatchery-Raised Trout

Researchers with Oregon State University in conjunction with the Oregon Department of Fisheries and Wildlife have found that fish (or, at least, steelhead trout) experience rapid DNA changes when raised in hatcheries rather than the wild. These changes are an adaption to the new environment that enable them to survive; the findings settle the ongoing debate about whether such rapid adaptions do, in fact, take place.

It only takes one generation from wild to hatchery for steelhead trout to show changes at the DNA level, according to researchers. More than 700 genes showed changes across that single generation, the study found, with those changes being passed on to offspring. Some of the genetics changes were pinpointed, while other traits remain a mystery at this point.

Genes that deal with things like wound healing, metabolism, and immunity showed changes, something that isn't surprising given the conditions of a hatchery. Unlike their wild counterparts, these farmed trout are raised in very large drums of water packed full of other fish, making for a very crowded environment in which food is provided rather than hunted and where there's little room for isolation.

Diseases and injuries are common in fish hatcheries.

Said OSU College of Science Professor Michael Blouin: "We expected hatcheries to have a genetic impact. However, the large amount of change we observed at the DNA level was really amazing. This was a surprising result."

From here, researchers may be able to determine exactly what changes are present from the wild fish to their hatchery-raised offspring. Understanding the changes may lead to ways hatcheries can alter their environments to avoid the changes, though all of that is yet to be seen. Regardless, the study provides a fascinating confirmation of evolution (very rapidly) at play.

Raising fish in large hatcheries isn't the only way a genetically altered fish may end up in your plate. In November, the FDA approved the sale of genetically modified salmon for human consumption, saying it found no issues with the meat.

Some precautions have to be in place, though, such as the fish being sterile to ensure they can't introduce their altered genes into a natural population. As well, the facilities harboring the GM salmon are limited in number and have systems in place to keep eggs and fish from reaching natural bodies of water.

Despite evidence towards the contrary, many critics still argue that genetically modified food is inferior or unsafe to eat.

SOURCE: EurekAlert