Meet Spider Goat - the DNA-enhanced web-flinging nanny that may one day knit bones

On a farm in Wyoming, USA, goats are being milked for their spider webs. And if that sounds bizarre, molecular biologist Randy Lewis claims that within two years, spider silk milked from goats could replace your body's tired or strained tendons and ligaments - maybe even bones. Professor Lewis and his team at the University of Wyoming have successfully implanted the silk-making genes from a golden orb spider into a herd of goats and are now, finally, producing one of nature's strongest products in useable quantities.

The technology is cutting edge, but the science isn't. Spider silk has been used for centuries to dress wounds with varying degrees of success, but the problem has until now been how to get it. "We needed a way to produce large quantities of the spider silk proteins," Prof Lewis said. "Spiders can't be farmed, so that route is out and since they make six different silks, even that would not work if you could."



Spiders also have a tendancy to eat each other, so milking one thread from six out of a solo spider was clearly never going to service the entire human race. Prof Lewis and his team singled out the "dragline" - the outer strand of the web - as the strongest of the six types of silk. They spliced the DNA that creates the silk into a female goat's DNA, then waited for it to give birth and start lactating.

"(The splicing) turned out to be relatively easy as there are known gene promotors that only produce expression in the mammary gland during lactation," he said. "Those were hooked up to our spider silk genes." After the milk is collected, it's taken back to a laboratory where the silk protein is filtered out. It solidifies when exposed to air and is wound onto a roller.



Prof Lewis said the team collects about four metres of silk for every four drops of protein they gather. The pure material had a wide range of medicinal applications as sutures and binding agents - including ligament replacement - but its use could extend well beyond our hospitals. "If it works, frankly one of the first applications is maybe fishing line," Prof Lewis said.

"I think we will be testing real world applications in less than two years (but) when they reach market is really beyond my control." Prof Lewis said there was no evidence to suggest the goats in the experiment behaved any differently to regular goats, in either physiology or "psychology".