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The GloFish

Glowing transgenic Zebra danios have just gone on sale in the USA with little legislative restriction from American authorities, as Matt Clarke explains.

Copyright © Practical Fishkeeping

Glow-in-the-dark transgenic Zebra danios have gone on sale in much of the USA with little legislative restriction from American authorities.

The GM fish, which are being sold under license from the National University of Singapore (NUS), have been trademarked under the name GloFish and marketed by Texas-based Yorktown Technologies. Two leading tropical fish suppliers, 5-D Tropicals and Segrest Farms, are distributing the fish to the aquatic trade.

Environmental groups were putting pressure on the US Food and Drug Administration (FDA) in the hope that they would step in and restrict the sale of the fish. They said that any decision to allow the sale of the fish will open a floodgate for other transgenic organisms to be marketed. However, in a terse statement, the FDA said it would not be restricting their sale because they pose no threat to the food supply and there is no evidence that the fish pose any more threat to the environment than their unmodified counterparts, which have long been widely sold in the United States.

Environmental groups in California have been successful in persuading the authorities to halt the sale of the fish, citing ethical concerns. California's Fish and Game Commission said it would not exempt the GM fish from the law, even if they didn't pose an environmental threat.

Commissioner Sam Schuchat told CNN: "For me it's a question of values, it's not a question of science. I think selling genetically modified fish as pets is wrong.

"To me, this seems like an abuse of the power we have over life, and I'm not prepared to go there today."

Yorktown Technologies asked the Californian authorities to allow it to make its GloFish exempt from existing controls on transgenic organisms, since the fish are not for food use and cannot reproduce but it rejected their proposal.

GloFish have already hit shops in Chicago, according to the Chicago Sunday Times. They cost from US$7.99-11.99 (�4.60-�6.90); an unmodified Zebra danio sells in the UK for about �1.

Somewhat ironically, although the fish were produced in Singapore, retailers there are not able to sell the fish due to issues with the licensing and problems in the laws surrounding intellectual property. Those importing GM fish into Singapore risk a S$10,000 fine or imprisonment. One supplier has already fallen foul of the law after importing transgenic fish from a supplier in Taiwan, where the fish have been on sale through the Taikong Corporation's Azoo Aquarium.

The transgenic fish, which have been dubbed the world's first GM pets, were originally developed at The National University of Singapore (NUS) to allow live fish to be used as highly sensitive biomonitors. Specific genes from glowing organisms that can be 'switched on' by aquatic pollutants, such as oestrogen or heavy metals, can allow the detection of pollutants.

The green danios contain a gene which encodes the green fluorescent protein (GFP) from a jellyfish while the pink form contains an additional gene from a coral which produces red reef coral fluorescent protein (RFP).

The NUS reportedly supplied several thousand transgenic danio embryos to Yorktown Technologies a year ago and is set to receive royalty payments for each fish sold.

Their creator, Professor Gong Zhiyuan of the NUS told the Straits Times: "It's a form of personal satisfaction to see fish lovers enjoying my creation. Hopefully, this will help the public understand and learn more about genetically modified animals, rather than fearing them."

Gong believes that they pose no environmental threat and says that the genetically modified fish can be more sensitive than their unmodified counterparts: "When fish were cultured under adverse slightly adverse conditions, the green transgenic fish were usually more susceptible to disease, thus causing higher mortality rates. The wild type fish generally ultimately grow to a bigger size than the transgenic fish. This may reflect the additional burden of expressing fluorescent proteins."

It is claimed that the GloFish have undergone a process of triploidisation to induce sterility, making them less of an environmental risk, but even without triploidisation the transgenic fish appear less fecund than their wild-type counterparts. Females are said to produce 50% less eggs, and males are 90% less fertile, than the wild-type. Mating choice experiments have shown that the fish have no fitness advantages, and Gong claims that "the fluorescence carries additional burdens in biosynthesis, energy distribution and predator avoidance."

Here in the UK, OATA believes that transgenic or genetically modified organisms (GMOs) aren't good for the trade. "OATA believes that the introduction of GM technology as is currently being envisaged is unwelcome and that GM fish have no place in the ornamental fish industry.

"The import of genetically modified fish to the UK is not a straightforward issue and members of OATA wishing to do so should carefully acquaint themselves with the relevant legislation available from the OATA office."

As far as GM fish being sterile, OATA says: "Arguments could rage over whether or not technologies to produce sterile fish are watertight. Certainly 'sterile' triploid salmonids don't seem to have completely read the textbook."

Stop Press
It appears that GloFish are not sterile! PFK reader Terry Wisener has recently contacted us to let us know that he has had several successful broods from his genetically modified fish.

Alan Blake, CEO of Yorktown Technologies told the magazine: "Aside from their brilliant color, fluorescent Zebra fish are the same as other Zebra fish in every way. This includes everything from general care and temperature preferences to growth rate and life expectancy.

"Accordingly, our fish are able to breed just as any other Zebra fish. At the same time, we encourage people to remember that their sale is covered by a substantial number of patents and related intellectual property. Because of this, any breeding and subsequent sale of the fish is prohibited."

GM fish in the UK

Since 2006 some dealers have been illegally selling GM fish in the UK. For more details see the following news stories:

Authorities confirm GM fish report
British aquarist bred illegal GM fish at home
Aquarium shops warned about potential GM fish

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Matt Clarke 999 (words, 10625 hits)
Published online: 01.07.04


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