When we talk about bioengineering new and better fish, it’s easy to let our
imaginations run wild. Wouldn’t you like to catch a GatorCat?
Alligator/Catfish Hybrids: Coming to a Pond Near You?
by Keith “Catfish” Sutton
It sounds like science fiction but it’s not.
Remember corny kids’ jokes like these?
What do you get when you cross a turtle and a porcupine? Answer: A slow poke.
What do you get when you cross a fish with an elephant? Answer: Swimming trunks.
Well, when we were kids, thinking that people could actually cross one animal with another very different animal seemed totally preposterous. In today’s world, however, genetic engineers are doing just that.
For example, you probably never thought scientists could cross spiders with goats, but now it’s being done. Researchers found a way to put spider genes in Nigerian dwarf goats to produce “spider goats.” Milk collected from these genetically altered farm animals contains spider silk protein that can be collected, purified and spun into synthetic spider silk fibers.
Real spider silk, the kind spiders use to weave their webs, is stronger than Kevlar, which is used in bullet-proof vests, stretches better than nylon and, weight for weight, is five times stronger than steel. The artificial silk refined from the goat milk mimics these properties and is being touted for use in automotive and aerospace components, high-tensile-strength medical sutures, artificial tendons, lighter body armor for law enforcement and military, and even … get this … biodegradable fishing line.
How about a pig crossed with a rodent? It’s been done. The resulting animals, dubbed “enviropigs,” have a gene made from the E. coli bacterium along with mouse DNA. The extra gene helps the pigs produce an enzyme in their saliva that sharply reduces the pollutant phosphorous in their manure.
Scientists in Japan have even inserted genetic material from spinach into pigs, which they say will produce healthier pork with less fat.
For years, mammals were the subjects of most bioengineering projects. Now fish have become the focus for many scientists.
At Auburn University, for example, researchers have come up with a clever way to protect catfish raised in hatcheries and aquaculture operations against some common diseases without medicating them. Previous studies have shown that cathelicidin, a peptide found in alligator blood, appears to have antimicrobial properties. It’s theorized that this evolved to protect the reptiles against infections following fights with other gators.
The Auburn team inserted the alligator gene that codes for cathelicidin into catfish, and as a precautionary measure, they made the insertion in part of the catfish genome that normally codes for a reproductive hormone. This renders the genetically modified fish sterile, ensuring they won’t be able to reproduce should they escape into the wild.
The alligator gene did exactly what the scientists had hoped it would do. The survival rate of the genetically modified fish was two to five times higher than controls when they were exposed to common infections. And the catfish were sterile unless they were artificially injected with hormone therapy.
If the Food and Drug Administration approves these genetically modified fish for human consumption (a process that could take years), use of the catfish hybrids could be a boon for the aquaculture industry. Farming fish that are resistant to disease will require fewer resources and produce less waste overall. And the sterile hybrids won’t pose a threat to wild gene pools.
Some experts regard such fish as the potential answer to the depletion of the world’s fisheries and a practical way to increase protein intake for many malnourished people. Increasing production of farm-raised fish, they say, could relieve the strain on wild populations pressured by overharvest.
That’s great news, but as we learn about these fascinating new technologies, it’s hard not to imagine the possibilities. Could we, for example, create strains of bioengineered “GatorCats” that would grow to enormous sizes and test our skills as anglers? Would it be possible to splice alligator genes with flathead or blue cat DNA to produce a 500-pound whiskerfish that could bite right through your fishing line … or your legs?
Could we cross other animals with catfish, too? It would be cool to see zebra cats with beautiful black-and-white stripes or perhaps a jaguar flathead with spots. We could give ugly old bullheads a makeover by crossing them with multi-colored butterflies or songbirds.
Speaking of birds, I wonder if it would be possible to cross catfish with our feathered friends to create new kinds of flying fish. Imagine an eagle-catfish hybrid. When it jumped, it would soar away with your cut-bait, compounding the thrills of the fight. And consider the possibilities of crossing parrots and catfish. Could we create talking fish? What would they say?
“Polly want some stinkbait.”
I’d really like to see a channel cat implanted with genes from a Holstein milk cow so the fillets would be full of butter and ready to sauté for a shore lunch.
Of course, we’d have to be careful with these experiments or we’d wind up like the folks in the 2004 movie “Frankenfish.” This story pits a pack of huge, mutant, flesh-eating fish against the human inhabitants of a bayou town. A genetic-engineering experiment gone horribly awry, these monsters are the result of a cross between a fish and a snake, and can travel on land as well as swim. They have a taste for blood, leaving a trail of gruesome corpses up and down the river.
I wonder what it would be like to hook one of those.
