April 18, 2024

TRY ANIMAL MODELS BEFORE CLONING HUMANS,     SAYS BRITISH SCIENTIST

Michael Cook

One of the best-documented critiques of cloning human embryos has appeared in the latest issue of the Journal of Medical Ethics. In an article entitled "Why the apparent haste to clone humans?" Dr Neville Cobbe, of the Wellcome Trust Centre for Cell Biology at the University of Edinburgh, asks why scientists are rushing ahead with human cloning before validating this approach with animal studies.

This point — often overlooked in debates — is a crucial issue. In a stinging challenge to supporters of embryo cloning, Cobbe points out that two inconclusive papers are the main props for the contention that no more animal research is needed. One reported an experiment which succeeded only with the help of adult stem cells and the other dealt with the brain, whose immunology is quite different from the rest of the body.

In recent months, especially after the Korean stem cell debacle, calls for therapeutic cloning have become more muted as the extent of the technical obstacles has become clearer. However cloning embryos for research is still strongly supported by most stem cell scientists. Cobbe points out, however, that even this approach is flawed because of significant variations in gene expression between clones. Ian Wilmut, Britain’s premier spokesman for cloning, admits that cloned offspring are more even variable than siblings. This implies that it might prove impossible to interpret studies which aim at identifying the subtle differences in the way drugs work on a genotype.

Cobbe acknowledges that "something resembling part of the promise of therapeutic cloning may become feasible some time in the distant future". But he argues that much more basic science is needed. In the meantime, scientists should concentrate on mouse models. "If we now allow such human experimentation without prior and thorough validation from humane work in other species, do we really know where we are going?"

Cobbe also stresses the potential for exploitation of humans. The first beneficiaries of any therapies would be the wealthy, as the cost of cloning will be very high. Obtaining eggs will be costly, risky and could exploit poorer women in the developing world. Cobbe concludes that "it would appear that a host of vested interests may have played a significant role in encouraging potentially profound misrepresentation of both the science surrounding cloning and its foreseeable clinical implications."

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