There is a quiet revolution going on in the world of cloning. Very few have heard of it, but its potential power is astonishing. Imagine a radical new way to clone that can not only create exact carbon copies of adults, but also allows the generation of important genetic improvements. Another you, but smarter, healthier, and maybe a bit better looking.
The birth of Dolly the sheep fifteen years ago shocked the world. We learned it is possible to replace the genes of an egg with those from an adult, and in a few cases the egg would proceed to make a viable clone, like Dolly. And the debates began! Should we allow human cloning? Was this a useful new reproductive option for childless couples? Or was it a crime against nature? Would clones have a soul? Were we moving towards a Brave New World future, with armies of clones fighting our wars and working in our factories?
The gene replacement technology used to make Dolly, however, was severely flawed. Only about one in a hundred eggs with genes from an adult survives. This procedure clearly should not be applied to people. For every birth there would be 99 aborted monstrosities, and even the rare clones surviving to birth are not really normal when examined carefully.
But recently we’ve seen a perfect storm of incredible advances in biology that changes everything. It is now possible to take adult cells, from the skin for example, and to transform them into stem cells, which can then be converted into complete individuals. It works quite well for mice, and there is every reason to think it would also work for humans.
How is this cloning through stem cells accomplished? The breakthrough was Shinya Yamanaka’s discovery that it is possible to treat adult cells with a special gene expression cocktail that turns them into the functional equivalent of embryonic stem cells. Stem cells, as the name suggests, are able to branch in many different developmental directions, to give rise to heart, nerve, liver, or other cell types. In the world of medicine, this is like the ancient alchemist somehow succeeding in turning lead into gold. Stem cells offer great promise in the regeneration and repair of diseased or damaged organs. Historically, the most powerful stem cells – those able to give rise to all of the different cell types of the body – were made from embryos. Hence the ethical controversy, since it was necessary to kill human embryos to make embryonic stem cells.
Adult derived stem cells made by the Yamanaka procedure, however, are as powerful as those made from embryos. They too can give rise to all of the cell types of the body. Indeed, it is possible to take adult derived mouse stem cells, grown in a plastic dish in the laboratory, and to turn them into complete mice. The controversy over human embryonic stem cells should now be officially over because we can make equally potent stem cells from adults, without sacrificing embryos.
Stem cell cloning, however, opens a Pandora’s box of possibilities. It is much more efficient than the gene replacement approach used to make Dolly. In addition, stem cells are extremely genetically malleable. Nobel prize winning genetic engineering technology works very well with them. It is therefore now feasible to clone not only exact copies, but also improved versions of people.
With the technical objections rapidly fading, it is now time to revisit the ethical issues of cloning. First, is it morally wrong to have multiple people with the same, or nearly the same, genes? Of course identical twins, triplets, quadruplets, and so on have long existed as a product of nature. But there are some differences between clones and twins. Twins are the same age, while a clone would be younger than its single parent. In addition, there is a limit on the number of genetically identical individuals that can be made by natural reproduction, but in theory a hundred or more clones could be made from one person. It makes most of us uncomfortable to think that a wealthy person could now make many young copies of him or herself.
Another issue is procreation without sex. Some people find the laboratory creation of human offspring repugnant, thinking it degrades and cheapens the process of reproduction. Are we heading towards a shopping catalog selection of our children? Nevertheless, the current methods of in vitro fertilization involve mixing eggs and sperm in the test tube, thereby creating human embryos for otherwise infertile couples. About one percent of all births in the U.S. are now the result of in vitro fertilization. Cloning technology is similar in principle, but using only one parent to make embryos instead of two. Does that difference make it morally wrong?
Our science and technology are marching forward at an ever accelerating pace. The topic could not be more important. We are talking about the nature of our children, and in the long run, our species. Genetic enhancement could lead to improved intelligence, and exceptionally long and healthy lives. Or a hellish dystopia. We must move into the future with great care.
About the Author: Steve Potter, PhD, is a Professor of Pediatrics, in the Division of Developmental Biology, at Children’s Hospital Medical Center in Cincinnati. He has authored Designer Genes: A New Era in the Evolution of Man, published by Random House 2010 http://www.amazon.com/Designer-Genes-New-Era-Evolution/dp/140006905X/ref=sr_1_1?s=books&ie=UTF8&qid=1310842010&sr=1-1. In addition he has written over one hundred science papers, and co-authored the third edition of the medical school textbook, Larsen’s Human Embryology.