The Future of Cloning
Seeds plans to open a
fertility clinic specializing in human cloning has
shifted the focus of the cloning debate towards human
cloning. However, most future cloning developments will
not concern the reproduction of humans, but will focus on
using cloning to better understand cell
development, heredity, and genetic structure. Cloning
will be used for far more than replicating an animal, or
reproducing a child. Here are possible future
developments in cloning research.
Transgenic animals are valuable to biomedical research and pharmaceutics and can be produced through nuclear transfer. If human genes are introduced into other organisms, like pigs and sheep, these transgenic animals can produce human proteins. These animals can be used as "drug factories," producing human proteins in its milk. They also produce insulin, used to treat diabetes. Also, transgenic sheep have been altered to produce produce alpha-1-antitrypsin, a drug that is used to treat cystic fibrosis. The current production of transgenic animals, using a micro injection of DNA into the nucleus of the fertilized egg, is inefficient. Not all of these eggs develop into transgenic animals, and the ones that do not always express the genes in a desirable way. Currently the production of transgenic animals is time consuming and expensive. With nuclear transfer, the introduction of DNA to somatic cell lines would occur in culture. Nuclei from cells expressing the human gene could be used for cloning, insuring all offspring would contain the transgene.
Cloning research may contribute to disease treatment by allowing scientists to reprogram cells. Through this research, for example, skin cells could be reprogrammed into the insulin producing cells in the pancreas. These skin cells would then be introduced into the pancreas of a diabetes patient, allowing them to produce insulin. Parkinson's Disease is a degenerative disease affecting neurons. Because neurons do not regenerate, cloning research could allow the reprogramming of cells into neurons to replace those damaged by Parkinson's.
Through cloning, organ transplantation may become a more successful process. Although organ transplantation is a common occurrence, there is often a shortage of organs suitable for transplantation. Xenotransplantation, transplanting organs from one species to another, provides a solution to organ shortage. However xenotransplantation often results in rejection because other organisms have different protein coats on the cell surface than human cells. Through nuclear transfer, transgenic animals could be produced that create human proteins on their cell surfaces. This common surface would reduce the risk of rejection during xenotransplantation. From future cloning research, human organs may be cultured from outside the body. In the future, humans might be able to clone their own organs for personal transplantation.
Cloning through nuclear transfer shows potential in agriculture. The current methods of breeding elite livestock involve artificial insemination of an animal with elite semen and embryo transfer. However, artificial insemination only provides half of the desired elite genes. This process is not efficient, and estimates suggest that the average cow is 10 years behind the best. Cloning would provide reproduction of the entire genome of an elite species, providing animals that only produce the best. In the future, farmers may receive cloned embryos that are guaranteed for performance. Also, mammalian cloning research would allow genetic manipulation to produce animals that are disease resistant. Clones of the transgenic animals would produce herds of superior livestock.
Nuclear transfer might provide techniques for genetic conservation. Imported breeds from commercial farming systems are replacing many local breeds. However, the local breeds may contain tolerance to local climate and tolerance to regional disease. The extinction of these local immunities needs to be stopped. Current conservation methods involve freezing and storing embryos. In the future, because of cloning technology, this practice would be less time-consuming and costly, thus making it easier to perpetuate a local line.
Through cloning, the genetic variability on farms may be increased. In the future, companies may produce a limited number of clones per genotype. The number of each cloned genotype sold to one farmer would be restricted. Although a herd might be all clones, the farmer would be able to interbreed the elite animals.
Cloning research may also help in the elimination of mitochondrial diseases. The mitochondria of a cell contain their own DNA, separate from the nucleus. Certain genetic diseases are carried in this separate DNA, inherited from the mother. Using a oocyte from a donor that does not have a disorder for nuclear transfer would eliminate the mitochondrial disease.
Future research in general may be benefited by cloning. Animals could be cloned especially for research. Genetically identical animals would reduce variability in experiments. Consequently, scientists would then need less animals for an experiment. Recently, scientists at the university of Hawaii have developed a new cloning technique that has proved to be more reliable than the method used by Ian Wilmut to create Dolly. Three generations of genetically identical cloned laboratory mice have been produced, indicating that cloning will be an indespensible tool to the research biologist in the future.
Cloning by nuclear transfer will allow the study of cell development, and the discovery of the mechanism by which cell development occurs. The process will also give insight into how cells specialize and differentiate. It will also explain how much the oocyte, egg, and cytoplasm contribute to early development, as compared to the nucleus genes. Cloning research will allow us to learn how to de-differentiate somatic cells, and then re-differentiate them into new cell types.
Copyright 1998 by team 24355 and Kayotic Development.