Silk in the Milk

A strand thinner than a human hair is stronger than steel. A strand the thickness of a pencil could stop a jet in flight. Spun into fabric, it can stop a speeding bullet. So what is it? Spider silk. The sought after substance has frustrated researchers for years. Attempts to "farm" spiders for their silk didn't work out well. Spiders tend to kill each other in close quarters. Instead, scientists tried to find a way to mass-produce a synthetic version of the stuff.

Now, thanks to genetic engineering and goats, scientists may get as close to the real thing as possible. Natural spider silk is a combination of proteins that spiders produce, which is forced through a winding path in their bodies, then out through spinnerets. The process "aligns" the proteins into the super-strong strand. Scientists isolated the genes that produce the silk proteins, and engineered them into goats' genes. The spider genes can then direct the goat genes to produce the silk proteins. The proteins are extracted from the goats' milk and turned into a spider-silk substitute. The process hasn't been perfected yet but researchers say they're closer than ever. Teams working on the problem say the silk would be perfect for parachutes, ropes, nets, artificial tendons and ligaments, aerospace tethers, and bulletproof clothing. What products can you think of? Is it ethical to alter the goats for this purpose?

Explore More: Genetic Engineering
Copyright 2004, Iowa Public Television
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