Imagine a society in which fish are raised in pens and fed food laced with dyes from genetically modified tomatoes in order to trick consumers into thinking that the fish on their plates grew up in the wild, swimming free, hunting, and being hunted. It sounds like something out of dystopian sci-fi, but that future is, potentially, right around the corner.
In the wild, fish such as salmon or trout eat crustaceans or insects with natural pigments that lend their flesh a pink or red tint. Fish raised in ponds or sea pens, however, receive no such natural coloration. Their flesh is often pale pink or even gray—not so appetizing to consumers used to a healthy pink. Fish farmers routinely add dyes derived from petroleum to the fish’s feed to mask this lack of wild coloration. But researchers think they’ve found a better way to procure these colorful edible additives. Rather than making dyes from petrochemicals, they’re growing the colorants in genetically modified tomatoes.
Marilise Nogueira, a graduate student at the Royal Holloway, University of London who led the project, says the goal was to find an alternate way to produce ketocarotenoids, the class of colorful compounds used to dye fish, in a way that doesn’t rely on environmentally harmful petrochemicals.
The enterprise says something about the cultural and scientific moment we’re in—turning to genetic modification to replace a petroleum-based product that is used to compensate for the removal of a natural process.
Humans have been dying foods produced by farmed animals for centuries or longer—often for similarly deceptive reasons. Butter, for instance, was routinely enhanced with annatto, a yellow dye derived from the seeds of the achiote tree. While undyed butter fluctuated in color, becoming more or less yellow depending on the time of year and diet of the cow producing it, using annatto extract allowed farmers to establish the color of “good” butter. Color was also added to cheeses and prepared meats such as sausages.
By the 1900s, organic dyes made from edible substances such as annatto, spinach, and saffron were largely superseded by synthetic dyes, which are cheaper to produce and more consistent in quality.
In the past few years, however, society has been shifting back from synthetic dyes to plant-derived ones, says food historian Ai Hisano from Kyoto University in Japan. Hisano sees the tomato-derived fish dye as fitting in with this shift, though in a very modern way.
Whether the genetically modified tomatoes are part of a dystopian vision or just the latest in a long line of agricultural deception, the work required some clever manipulations of the tomatoes’ genes to get the dyes required.
Naturally, tomatoes produce similar dyes called carotenoids, which give them their signature red color. But tomatoes do not make these compounds in high enough concentrations to make them a viable colorant for fish feed.
So, using a variety of tomato called Moneymaker that had been genetically edited to add bacterial DNA associated with producing ketocarotenoids, the researchers engineered a tomato to make those different colorful compounds. But the gene editing by itself wasn’t enough to get the necessary high-yield tomato.
by Kat Eschner , Hakai | Read more:
In the wild, fish such as salmon or trout eat crustaceans or insects with natural pigments that lend their flesh a pink or red tint. Fish raised in ponds or sea pens, however, receive no such natural coloration. Their flesh is often pale pink or even gray—not so appetizing to consumers used to a healthy pink. Fish farmers routinely add dyes derived from petroleum to the fish’s feed to mask this lack of wild coloration. But researchers think they’ve found a better way to procure these colorful edible additives. Rather than making dyes from petrochemicals, they’re growing the colorants in genetically modified tomatoes.
Marilise Nogueira, a graduate student at the Royal Holloway, University of London who led the project, says the goal was to find an alternate way to produce ketocarotenoids, the class of colorful compounds used to dye fish, in a way that doesn’t rely on environmentally harmful petrochemicals.The enterprise says something about the cultural and scientific moment we’re in—turning to genetic modification to replace a petroleum-based product that is used to compensate for the removal of a natural process.
Humans have been dying foods produced by farmed animals for centuries or longer—often for similarly deceptive reasons. Butter, for instance, was routinely enhanced with annatto, a yellow dye derived from the seeds of the achiote tree. While undyed butter fluctuated in color, becoming more or less yellow depending on the time of year and diet of the cow producing it, using annatto extract allowed farmers to establish the color of “good” butter. Color was also added to cheeses and prepared meats such as sausages.
By the 1900s, organic dyes made from edible substances such as annatto, spinach, and saffron were largely superseded by synthetic dyes, which are cheaper to produce and more consistent in quality.
In the past few years, however, society has been shifting back from synthetic dyes to plant-derived ones, says food historian Ai Hisano from Kyoto University in Japan. Hisano sees the tomato-derived fish dye as fitting in with this shift, though in a very modern way.
Whether the genetically modified tomatoes are part of a dystopian vision or just the latest in a long line of agricultural deception, the work required some clever manipulations of the tomatoes’ genes to get the dyes required.
Naturally, tomatoes produce similar dyes called carotenoids, which give them their signature red color. But tomatoes do not make these compounds in high enough concentrations to make them a viable colorant for fish feed.
So, using a variety of tomato called Moneymaker that had been genetically edited to add bacterial DNA associated with producing ketocarotenoids, the researchers engineered a tomato to make those different colorful compounds. But the gene editing by itself wasn’t enough to get the necessary high-yield tomato.
Image: Olena Danileiko/Alamy
