Cloning is the process of creating a genetically identical duplicate of an organism. A clone is said to be all descendants derived asexually from a single individual. Scientists plan to use somatic cell nuclear transfer for the first human clone, which is the same technique that was used to create Dolly the sheep. Somatic cell nuclear transfer is accomplished when:
1. An egg is taken from a donor and the nucleus removed creating an enucleated egg.
2. A somatic cell (a non-sperm, non-egg cell), which contains DNA, is then taken from the person to be cloned.
3. The enucleated egg is then fused together with the somatic cell using electricity.
4. This creates an embryo, which is implanted into a surrogate mother through in vitro fertilization.
This process is far from perfect. The removal and re-introduction of the nucleus, the electric stimulation of the cell, and the in vitro fertilization all combine to make viable embryos in only about 1 in 200 attempts. And then, the results are less than predictable. Returning to our previous mention of Dolly, it is important to note that her life span was only about 1/2 that of a normal sheep. Nevertheless, these difficulties will be overcome and human cloning will be a reality within the decade.
How Does Cloning Relate to Future Human Evolution?
Cloning may be a factor in the future of human evolution but will certainly not be its primary driver. We believe it will increase our individual longevity and contribute to healthier, happier lives through organ replacement, and eventually cloning technology will enable the seed ship method for propogating our species throughout the stars. While it may provide other hypothetical benefits such as re-creating brilliant scientists, philosophers, and humanitarians who might then have more than a single life time to contribute to our evolutionary development, advances in direct manipulation of the genome will probably allow us to specify the genetic pattern of those we would want to emulate.