The silk produced by spiders to make their webs has some fairly special structural properties. It is quite strong, similar in tensile strength to nylon, but is much more elastic (it can be stretched more without breaking or deforming). It has been used for certain limited applications: for example, to make cross-hairs for optical instruments, and is potentially useful in many other applications:
For instance, due to its strength and elasticity, spider silk fiber could have several medical uses, such as for making artificial ligaments and tendons, for eye sutures, and for jaw repair. The silk could also have applications in bulletproof vests and improved car airbags.
Its wider use, though, has been limited by the difficulty of obtaining it in quantity. Spider “farming” has been tried, but spiders are territorial, and the experimental participants tend to end up eating each other.
Now, according to an article at PhysOrg.com, a group of scientists at the University of Wyoming has developed a method for inserting the spider genes that control silk production into goats. Some of the resulting goat offspring will then produce the protein that makes up spider silk in their milk. The protein can then be extracted from the goats’ milk, and purified into relatively large quantities of silk. So far, the goats do not seem to suffer any adverse consequences from the genetic tinkering. The work is described in more detail in an article at the National Science Foundation Web site.
The research group is now exploring the possibility of putting the silk gene into alfalfa plants. Alfalfa is a widely-planted crop, which is less unruly and malodorous than goats. It also has a relatively high protein content, so the potential yield of the silk protein might be quite large.