Transgenic glowing fish invades Brazilian streams

[Judi Lynn]

Aquarium curiosity appears to be thriving after escape from fish farms and may threaten local biodiversity

11 FEB 20226:05 PMBYSOFIA MOUTINHO



Genetically modified zebrafish (Danio rerio) are sold in fluorescent red, blue, and green.PAULO DE OLIVEIRA/MINDEN

Fish genetically engineered to glow blue, green, or red under blacklight have been a big hit among aquarium lovers for years. But the fluorescent pet is not restricted to glass displays anymore. The red- and green-glowing versions of the modified zebrafish have escaped fish farms in southeastern Brazil and are multiplying in creeks in the Atlantic Forest, a new study shows. It is a rare example of a transgenic animal accidentally becoming established in nature, and a concern for biologists, who worry the exotic fish could threaten the local fauna in one of the most biodiverse spots on the planet.

“This is serious,” says ecologist Jean Vitule at the Federal University of Paraná, Curitiba. Vitule, who was not part of the research, says the ecological impacts are unpredictable. He worries, for example, that the fluorescence-endowing genes from the escapees could end up being introduced in native fish with detrimental effects, perhaps making them more visible to predators. “It’s like a shot in the dark,” he says.

The unwelcome visitors are well known to scientists who have used zebrafish (Danio rerio) for developmental and genetic studies for decades. Native to Southeast Asia, the match-size freshwater fish are brightly colored naturally. But the animals were engineered to glow for research purposes in the late 1990s by endowing them with genes from fluorescent jellyfish (for blue and green colors) and coral (for red). In the 2000s, companies saw the potential of the neon fish as pets. Trademarked as Glofish, they became the world’s first genetically engineered species to be commercially available.

Now, they are one of the first to escape and thrive in nature. Early on, environmentalists worried about the possibility, and Glofish sales were banned in some U.S. states such as California and several countries—including Brazil.

More:
https://www.science.org/content/article/transgenic-glowing-fish-invades-brazilian-streams

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