October 21, 2002
Human Genes Put Into Pig Sperm
A new method for putting genes into an animal species by gene therapy on sperm has been tested in pigs:
Genetically-modified animals can be created simply by washing sperm, swishing it in a centrifuge with an additional gene, and using the altered sperm for artificial insemination, say Italian researchers.
Marialuisa Lavitrano's team at the University of Milan-Bicocca in Milan have demonstrated how well the simple method works by creating pigs that could one day provide rejection-free organs for transplantation into people. The technique worked 25 times more efficiently than the standard way of engineering animals.
Pigs are being used because genetically modified pigs are excellent candidates as methods to grow replacement human organs:
"In the U.S., every 18 minutes a person dies on the waiting list for organ transplants without receiving one. Every 18 minutes is a lot. Xenotransplation could really be a solution," lead researcher Marialuisa Lavitrano, an immunologist and pathologist at the University of Milan-Bicocca, told United Press International.
This sperm-based technique also is relatively cheap and about 14 to 114 times more effective at implanting genes in pigs than the direct injection of DNA, the most common way of making genetically engineered animals.
This method is cheaper and has a higher success rate than gene injection:
Ninety-three piglets were born after the researchers tinkered with the pig sperm, and 57 percent of them contained the human gene, suggesting the sperm soaked it up from the solution. When researchers injected sperm with the gene, only 4 percent of the piglets born had the gene inside them.
These researchers are pursuing the development of this technique in order to be able to transplant a large number of human genes into pigs. Their goal is to create pigs which would contain internal organs that would be sufficiently compatible both physiologically and immunologically to allow transplantation into humans. My guess is that this technique alone will not be sufficient to do the amount of genetic engineering that will be required to achieve this ambitious goal. It may be necessary to both remove and add genes in order to create pigs with all the desired biological qualities. Also, the process of adding the sheer number of required genes may end up causing harmful mutations in the sperm chromosomes. Still, its a great piece of research.
There is another obvious purpose that this technique might eventually be used for: human progeny genetic engineering. Human sperm could be treated using the same technique in order to put desired genes into human progeny. Of course, the technique might require a much greater degree of refinement in order to prevent harmful mutations. One potential risk is the possibility that any gene transplanted into sperm chromosomes could get incorporated into the middle of an existing gene. That could cause harmful genetic defects in progeny that would manifest at birth or at a later time in life.
Update: This story from CNN confirms that deletion and modification of existing genes are also necessary to make pigs suitable for xenotransplantation:
"You can add a gene, but you cannot alter or remove a gene using this technique," said Prather. It is known that some other genes will have to be altered or removed in order to create animals for the xenotransplantation of organs, he said.
Wow. That's so simple you can do it at home, provided you could get a solution of the desirable gene.
This should go a long way to making genetic engineering unsuppressable. You can't stop people from doing things with sperm and a willing female.
And the possible problems would be easy enough to investigate. Just try it with another 1000 pigs and see if there are any problems.
Patrick, yes, genetic engineering can not be stopped. It can only be delayed. More generally, people will have mini chemistry labs built using silicon chips and other materials and they will be able to make drugs, genes, and other things in the privacy of their own homes.
It is difficult to say whether this trend toward individuals being able to do more with technology will be a net benefit or threat to human civilization. After all, someone could make a killer virus with a nanotech home biochemistry constructor set.
So how long before we see people selling vials of "tallness gene" or "leaness gene" for $200?
After all it is simple enough for a postgraduate biotech student to whip up in the lab, and there would definately be a market for it.
"Intelligence genes" or "richness genes" would be impossible with our current level of knowledge, but if the parents-to-be needed more intelligence genes then they wouldn't know that would they...
I don't believe it will take much longer to find some genetic variations that affect intelligence than it will to find genetic variations for a variety of visible physical characteristics. The key factor is very simple: how fast will the cost of DNA sequencing come down? Once it becomes cheap enough for individuals to get themselves sequenced then large numbers of people will be sequenced and their sequences compared with each other along with their health, personalities, intelligence, visible characteristics (hair color, height, build, etc), and other characteristics that vary between humans. Once total personal genome sequencing is affordable many different genetic causes of many different human characteristics will be teased out at the same time.
So how fast with DNA sequencing costs fall? Go back into the August, September and October archives for futurepundit (links on the right of the main page under Archives) and you can find a number of posts I've made on the subject. My guess is that personal DNA sequencing will cost less than $1000.00 in under 10 years.
Wow, incredible research. I find it tough for the pigs though - especially if they got smarter. Plus what will the life expectency be of organs harvested from pigs who have different diets and life-spans then humans? On another note, it won't encourage people to pursue a healthy life-style, knowing they can always get a new heart or liver from a pig.
Anne, Yes, the shorter lifespan of a pig probably translates into organs that do not last as long. The ability to put human genes into the pig holds out the hope of making the organs last longer. We'd need to identify which genetic variations shorten pig lifespans and either replace those genes with their human equivalents or modify the pig genes to fix the factors that are shortening lifespan.
Also, keep in mind that if xenotransplantation becomes possible and someone gets a pig organ that will only last, say, 15 years then during that time methods to develop longer lasting organs will be developed.
Yes, we can expect people to become more irresponsible if they know they can get their bodies repaired.
I have been tinkering with the idea of implanting human fertilized eggs into pigs for gestation. I believe that pigs could carry 2-3 human babies at one time. The mother pig might be capable of many births. If caesarian births are required due to the human's large size, the pig could be used for food as well, although this probably seems rather bizarre to people who consider mothers to be sacrosanct.
Scientifically, considering the closeness of pig DNA to human DNA, how difficult would it be to implant and carry to term a human or two in a pig?
Could this not be the answer to women in industry who want a child but for business reasons or health reasons does not want to carry that child herself? What about women who cannot have children due to other reproductive challenges?
DID YOU People consider GOD.... in this great theme..an the tiny SOUL, that would suffer..especally if it came out haveing pig parts...THAT would be a genictic possibillity...Not only to that.. they will end up being used to enrich the meat as they may develope larger with our genes , like pepsi wanting to use baby stems to better the tast of pepsi...YOU will be cannibals...eating your own kind...