Genetic Engineering and the Spider Goat

“Spider Pig, Spider Pig, does what ever a spider pig does, can he swing from a web? No he can’t he’s a pig, look out here comes the Spider Pig” sang my hero Homer Simpson in The Simpsons Movie. Close Homer but no cigar. Actually whilst there is no connection between spiders and pigs there is, would you believe, a spider goat. Seriously. There is a spider goat. Not entirely surprisingly in so many ways, the spider goat originated in America.

Borrowed – or if you prefer – shamelessly lifted from Britain’s Observer newspaper website :

“Freckles looks like a perfectly normal kid. She has bright eyes, a healthy white pelt and gambols happily with Pudding, Sweetie and her five other siblings, exactly as you might imagine young goats do. Until I fend her off, she’s very keen on chewing my trousers. To the casual observer, and to goatherds, she shows no signs that she is not a perfectly normal farmyard goat.

But Freckles is a long way from normal. She is an extraordinary creation, an animal that could not have existed at any point in history before the 21st century. She is all goat, but she has something extra in every one of her cells: Freckles is also part spider.

That is what we can now do with genetics: extreme cross breeding. If 20th-century biology was about taking living things apart to find out how they work, the current era is defined by putting them back together, but not necessarily as evolution decreed, and certainly without the clumsy constraints of mating. Freckles is the result of genetic engineering. But our mastery of manipulating DNA has evolved into an even more extreme form of tinkering, broadly called “synthetic biology”. I’ve been tracking this emerging field since finishing my PhD in genetics 10 years ago, but intensely in the last year as a presenter for the BBC’s flagship science strand, Horizon.

Freckles is the creation of Randy Lewis, a professor of genetics at Utah State University. The farm is a university outpost where they research modern farming techniques, teach animal husbandry and raise what are inevitably referred to as “spider-goats”.Randy, like many of the other scientists here in Logan, Utah, has farming in his blood. So although a creature that is part goat, part spider might seem like an idea born of science fiction, as far as Randy is concerned it’s simply advanced farming: breeding animals to produce things that we want.

“We’re interested in dragline silk – the silk that spiders catch themselves with when they fall,” he tells me in his midwest lilt. “It’s stronger than Kevlar. It really has some amazing properties for any kind of a fibre.”

In a sense, spider-goats are an extension of the farming we’ve been doing for 10,000 years. All livestock and arable has been carefully bred, each cross being a genetic experiment of its own. “The trouble is, you can’t farm spiders,” Randy says with an almost comic deadpan face. “They’re very cannibalistic.” He and his team took the gene that encodes dragline silk from an orb-weaver spider and placed it among the DNA that prompts milk production in the udders. This genetic circuit was then inserted in an egg and implanted into a mother goat. Now, when Freckles lactates, her milk is full of spider-silk protein.

We milk Freckles together and process it in the lab to leave only the silk proteins. With a glass rod, we delicately lift out a single fibre of what is very obviously spider silk and spool it on to a reel. It has amazing, and desirable, properties, which is why Randy’s seemingly bizarre research is so robustly funded. “In the medical field, we already know that we can produce spider silk that’s good enough to be used in ligament repair,” he tells me. “We already know we can make it strong enough as an elastic. We’ve done some studies that show that you can put it in the body and you don’t get inflammation and get ill. We hope within a couple of years that we’re going to be testing to see exactly the best designs and the best materials we can make from it.”

The instructions for all creatures that have ever lived (as far as we know) are written in the code of DNA tucked away in the heart of living cells. Given the bewildering diversity of life on Earth, this system is incredibly conservative. All life is based on an alphabet of just four letters, which, when arranged in the right order, spell out proteins. And all life is made of, or by, proteins. So what this means is that the code for making silk in a spider is written in exactly the same language as the code for making goats’ milk.”

So there you have it. Spider Goat. We, humanity, have actually created a spider goat. It may well be that the goats are 99.99999% goat but the fact that they have a miniscule amount of spider in them is freaky don’t you think?

What do have to say about that Homer?

“Spider goat, spider goat, does what ever a spider goat does, can he spin a web? Yes he can cause he’s a – goat??”

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