- Education and Science
BioEngineering: Turning Goat Milk Into Spider Silk (BioSteel)
Goat milk with a little extra protein - bizarre science!
At first glance, Freckles may look like any other goat. She has four legs, two ears, two eyes, a mouth and a nose. Indeed, Freckles looks and acts just like any other farmyard goat. However, Freckles is no ordinary goat. She is the creation of Randy Lewis, a professor of genetics at Utah State University. She is the product of a complex crossbreeding that has produced a super hybrid. Freckles is part goat and part spider.
Yes, that's right. Freckles is part spider.
Freckles is the result of a particular branch of genetic engineering called synthetic biology. While this might sound like a case of extreme bioengineering or science fiction, for Randy Lewis it is simply advanced farming. For him, it simply means to produce an animal that produces something you want.
What Is spider silk?
Spider silk is one of the seven great wonders of the animal kingdom. This tiny little creature, the spider, an arachnid, can make a substance that we humans with all our technology are unable to reproduce. It is a substance so tough that it is stronger and more flexible than anything else we know, even stronger than steel.
Spider silk is able to absorb a great deal of moisture. The more moisture it absorbs, the less brittle and the more elastic it becomes. Spider silk has another amazing property. It is actually quite acidic and is not attacked by bacteria or fungi, which is why cobwebs remain around for so long.
Spider threads consist of long chains of thousands of repeating sequences of protein molecules. These silk proteins are stored in the silk gland in a highly concentrated form until they are needed.
There are a lot of things about spider silk that are still not fully understood. What we do know is that it is one of nature's most amazing commodities and something that has possibly endless applications in our modern world.
Target: dragon silk
Researchers have been interested in dragline silk for many years. This refers to the specific silk that spiders use to catch themselves as they fall. It is the silk they 'ride the wind' with. It has amazing properties and has been found to be stronger than kevlar, a synthetic fiber that was developed at Dupont in 1965 that is five times stronger than steel and has been used as a replacement for steel in racing tires. It has also been woven into body armor.
So, why farm goats? Why not just farm spiders?
In short, because spiders are hard to farm. They tried this, but the truth is, spiders are very territorial and tend to kill each other when they come into close quarters. That's not exactly very productive farming. It also takes a lot of spiders to produce the quantity of silk they wanted. This wasn't very efficient.
However, goats are a much easier animal to work with.
So the next logical question is, how did they manage to get the silk protein to show up in the goat's milk?
It turns out that the silk protein is very similar to a protein already present in goat's milk. Randy Lewis 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 of the goat. This genetic information was then inserted in an egg and implanted into the mother goat.
Freckles was born, along with other siblings. Now that Freckles is an adult, and ready to have her own kids, when Freckles lactates, her milk is full of spider-silk protein.
It turns out that in this instance, mixing spider DNA with Goat embryos produces milk... with a side of silk! Biotechnology in this case is udderly amazing... excuse the pun!
How do you get the spider-silk protein out of the goat milk?
When Freckles is milked, they process the milk in the lab to leave only the silk proteins. With a glass rod, he delicately lifts out a single fiber of what is obviously spider silk and spools it onto a reel. It has astoundingly desirable properties, which is why Professor's Lewis' seemingly bizarre research is funded so generously.
What applications are there for spider silk?
Because of its inherent strength, it is already known that they can produce spider silk that can be used in artificial tendon and ligament repair, eye sutures, and jaw repair. The advantage is that it can be made as strong as an elastic, and you will be able to put it in the body without getting inflammation or getting ill.
There are also applications to use the spider silk in bullet proof vests or other protective body armor. Right now, there are vests that protect vital organs and helmets that protect the brain. Even so, the head is still relatively exposed, as one could easily still penetrate the skull using a high powered bullet with a head on shot through the face. There is research being done now with spider silk utilizing protective body wear that would provide effective defensive coverage for the entire head.
At this point, the possibilities are still being researched. There are many directions to go with the spider silk, so the future looks promising.
Do you think that genetic engineering goes too far?
Are goats the future of spider silk?
The answer to this question is, maybe... but maybe not. Goats are still animals which means they have to be cared for: fed, watered, sheltered. This takes a lot of time. It takes time for a goat to grow up. It takes time for them to become pregnant. It takes time for them to begin to lactate. Also, according to the law of genetics, only a certain number of goats will end up with the gene.
Researchers are now studying how to incorporate the gene into alfalfa plants, which will be able to produce an even larger quantity of silk. Alfalfa crops are much less work, and so the idea lends itself much better to mass production.
Genetic engineering or genetic tampering? The ethics debate
The ethical debate on genetic engineering goes on. For sure, it is heard loudly on both sides.
The instructions for all creatures that have ever lived are written in the code of DNA and exist in the living cells. All life is based on an alphabet of just four letters, which, when arranged in the right order, spell out proteins. 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 goat's milk. This also means that it makes it increasingly within our reach to rewrite the code on many things, even though it's a complex process.
Since the advent of genetic engineering, we have been able to exploit the universality of this code and cut and paste bits of DNA from any one species into any other. In some instances and applications, this has been helpful. For instance, it has helped us to identify the genetic basis of all cancers and inherited diseases. Now, this editing technology has progressed to the extent that all bits of DNA code are effectively interchangeable between some species. The loosely defined field of synthetic biology has come to incorporate even more extreme forms of genetic tinkering.
But where do we draw the line? When does genetic engineering become genetic tampering? Where do we draw the line and who decides the difference between a potential scientific breakthrough or benefit and a possibly harmful, destructive genetic mutation?
This is not an easy question for anyone, not the scientist, not the consumer, not the person who may gain benefit from the study, and not even the industry who gains financially from it. There are no easy answers.
The only thing we can do is learn to be responsible with this technology. We should realize the need for continuous negotiation with moral notions and beliefs with the purpose of directing and influencing policy as a result of this mutual interaction.
There are organizations out there who do just this.
Basically, these organizations should monitor advancing technology rather than simply react to it. The bottom line is that science should raise ethical issues and try to solve these ethical issues, and these same ethical issues should influence science. This creates a healthy tension and a balance between genetic engineering research and ethical boundaries. Maybe in this way, we can avoid the potentially harmful consequences of unmonitored science through an unbalanced approach.