Reproductive Cloning – Harms to the Mother and Harms to the Clone

A human clone can’t be created by methods available today. The process of cloning mice is now fairly well-established. African wildcats have been successfully cloned by Dr. Betsy Dresser, Director of the Audubon Center for Research of Endangered Species. Research on primate cloning, done at the Oregon National Primate Research Center, has led to the creation of cloned rhesus monkey embryos. The results were reported in November 2007 inĀ Nature, and described the derivation of embryonic stem cells from the cloned blastocysts. This was a significant breakthrough in the field of reproductive medicine. Yet work on cloning itself has not proceeded any further than the ability to produce cloned early embryos in rhesus monkeys.

The practical challenges to human reproductive cloning are huge. Additionally, of course, there are formidable ethical challenges. On the practical side, all the potential obstacles relate to the fact that cloned embryos are not the same as embryos created by sexual reproduction. These latter “standard” embryos are the products of two haploid sets of chromosomes. Millions of years of evolutionary refinement have developed the processes by which an embryo is formed. Embryos created by somatic cell nuclear transfer (SCNT) break this process. At present cloned embryos are created by brute force. SCNT in its initial iteration used a jolt of electricity to fuse the injected donor nucleus with the cytoplasm of its enucleated egg host. Researchers are now using more refined methods – involving various chemical cocktails – to cause the two disparate components to fuse and begin the process of development. For more details please visit these sites:-

The list of developmental processes that are broken by SCNT is long. Embryologic development involves deep and complex events. The circumstances may be relatively well understood, but the biochemical mechanisms are at best poorly described and at worst completely unknown. For example, the processes by which the egg cytoplasm reprograms the sperm DNA’s set of epigenetic marks are completely unknown. In cloning the egg cytoplasm must reprogram a diploid set of chromosomes, twice as many as the haploid number contained in the sperm. Also, somatic chromosomes contain epigenetic marks that vary significantly from those of sperm chromosomes. The sperm’s configuration has been modified extensively during the process of sperm production, i.e., gametogenesis. The effects on the developing embryo of these several contrasts in epigenetic management are completely unknown at present.

Privately funded researchers, imagining themselves to be free of ethical constraints, might push ahead and force the issue without waiting for new findings to emerge from legitimate science. The consequences for the mother-to-be, gestating a cloned embryo in her womb, could be disastrous, even fatal. If a live birth is obtained, that child’s health could be at risk for his entire life.


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