Choosing Our Genes: Attempts to Ban Biomedical Research Are Announced Almost as Frequently as Reports on Breakthroughs. A Medical-Technology Analyst Argues That the Bans Are Premature and May Do Society More Harm Than Good

Article excerpt

Technologies giving us control over our genetic destiny will be developed, whether they are banned or not. But clumsy regulatory efforts could greatly impede our progress toward improving the future health and well-being of our descendants.

What is causing all the fuss are technologies that will give parents the ability to make conscious choices about the genetics and traits of their children. For the foreseeable future, genetically altering adults is not in the cards, other than for treating a handful of specific diseases like cystic fibrosis. Changing the genes of an adult is far too daunting, and there are simpler, safer, and more effective ways of intervening to restore or enhance adult function.

Germinal choice technology refers to a whole realm of technologies by which parents influence the genetic constitutions of their children at the time of their conception. The simplest such intervention would be to correct genes. It is not a particularly radical departure, since it would have exactly the same effect as could be accomplished by screening multiple embryos and picking one with the desired genes. In fact, such embryo screening is being done now in preimplantation genetic diagnosis. Such technology has been in use for more than a decade, but what can be tested for is going to become increasingly sophisticated in the next five to 10 years. And as these technologies mature, the kinds of decisions that parents can make will become much more complex.

Farther into the future will be germline interventions-alterations to the egg, sperm, or more likely the first cell of an embryo. These procedures are being done already in animal systems, but using approaches that don't have the safety or reliability that would be required in human beings.

One approach that might bring the greater reliability needed for humans is the use of an artificial chromosome. That technology sounds like flimsy science fiction, but it is already in use in animal systems. Artificial chromosomes have been added to rats and passed to several successive generations. They have also been used in human cell cultures and remained stable for hundreds of cell divisions. Thus, they could provide a stable "platform" that could be used for the insertion of whole modules of genes. These inserts would include the requisite control elements to turn the genes on and off at the appropriate time, just as our normal genes in our 46 chromosomes are activated or deactivated, depending on the type of tissue they are in or the conditions and influences that they experience.

For safety, you would want early interventions to be very narrow in focus, of course. You wouldn't want to modify a gene that is typically "on" in a whole variety of tissues during fetal development, because we don't know much about that process, and undesirable or damaging secondary effects would likely result. So the first attempts to use an artificial chromosome in humans would likely set any added genes in the "off" position so they would not be expressed until an adult stage, when they would be turned "on" in the proper tissue.

The mechanisms for exerting such control are already in use in animal experiments designed to see the effects of specific genes in an adult organism. There are, of course, controls on genes that do just that in the body all the time. Different sets of genes are turned on and off at different times and different places in different tissues, which is fortunate for future genetic engineers, because the proven regulatory structures associated with our existing genes might be copied to exert similar control over inserted genes.

Goals of Germinal Choice

The prevention of disease will likely be the initial goal of germinal choice. And the possibilities may soon move well beyond the correction of aberrant genes. Recent studies suggest, for example, that children who have Down syndrome have close to a 90% reduction in the incidence of many cancers. …