human cloning

Another was to address diseases requiring genetic change in many different organs whose cells do not divide in adults (such as muscle, heart, and nerve cells), requiring modification before organs differentiate during embryonic development (Wivel 1993, 95).

All nations that have explicitly addressed germ line gene therapy have opted to constrain it. In the United States, the “will not entertain proposals” language of RAC prevails. As noted before, Germany, Denmark and some other nations have made germ line alterations in humans a criminal act. In the United Kingdom, the experiments are subject to a licensing authority that was created by law. The licensing authority has discretion, but only within statutory parameters. The legislative language has caused some problems in the case of a mother who desired fertilization using the sperm of her husband, whose sperm was obtained and frozen after he was comatose and could not give written consent for its use. The artful solution in this case has been to export the sperm to another European Union country, where the fertilization and insemination can take place.

The proscriptions on germ line intervention were largely academic but edged toward more concrete form in 1995, when Donald Rubinstein and colleagues proposed “a nine step protocol at the germ-line level for the curative treatment of a genetic disorder.”48 The protocol was unexpected because it focused on mitochondrial disease, thus framing germ line intervention in a new way.

Mitochondria are small membrane-enclosed organelles inside most cells in the body. They contain several dozen genes, some of which cause diseases when mutated. Mitochondria are not inherited with the other chromosomes, but reside in the mother’s egg at time of fertilization, and so inheritance is exclusively maternal. All children of an affected woman are at high risk, although expression can be variable, depending on the severity of the mutation, on whether all mitochondria are mutated or there is a mix of mitochondrial gene types, and on modulation by other genes.

The proposed protocol would fertilize the egg of an affected woman with her husband’s sperm, thus making the nuclear genes the usual 50-50 mix of mother’s and father’s genes. The nucleus of the mother’s egg would be removed, however, and placed into the enucleated egg of another woman before fertilization. This would replace the mother’s cytoplasm, containing the mutated mitochondria, with the donor woman’s just before fertilization. Like other children, the resulting child would retain the nuclear genome of the mother and father but all mitochondria would derive from eggs of the donor woman.

The child’s cells would be genetically altered, but not in the way most writers addressing germ line intervention have assumed. This protocol entails manipulation of an egg and not an embryo, but depending on details of language, the technique might or might not be covered by proscriptions intended to thwart embryo research and in vitro fertilization. The technique certainly causes inherited changes in subsequent generations, and in that sense is a germ line manipulation.

It does not entail recombinant DNA, however, and so would not be subject to RAC review unless H-17