Genome Project, Gene Therapy, and Killer Genes
by Irma S. Jarcho
In May 1998 Mount Sinai Hospital in New York City offered a pair of lectures on "Genome Project, Gene Therapy, and Killer Genes" by Drs. Kurt Hirschorn and Jon Gordon. Among the insights offered by these lectures can be noted the following:
Of the total DNA in the human body only 3% to 5% are genes -- the rest is what is considered to be "junk" DNA. Humans have between 60,000 and 100,000 genes, only 2000 of which have been sequenced and which represent only 300 million of the six billion DNA base pairs. Even though the number of genes sequenced to date is low, some important facts have emerged. To start with, there is enormous variation among individuals -- even identical twins differ by 1%.
Genes associated with important diseases have been identified. To date researchers have been able to sequence genes for such diseases as cystic fibrosis, Tay Sachs disease, and sickle cell anemia. Perhaps more important, they have worked out which genes create susceptibility to some common diseases. Physicians had always suspected that some diseases "ran in families." Now they have been able to pinpoint which genes are involved. Among the known diseases with a genetic component may be listed asthma (one gene), obesity (two genes), myocardial infarction (at least four genes), and hypertension (one gene). Of even greater interest is the fact that there seems to be a genetic factor at work even in infectious diseases. Among these are AIDS, malaria, and tuberculosis. The possible effects of a genetic map on employment, health insurance, and life insurance make it imperative that strict control be exercised on issues of confidentiality.
Dr. Gordon spoke against restricting work on cloning of human cells. Promising avenues of research would be cut off -- for example, correction of a genetic disease by gene replacement (gene therapy). Gordon also stated that mice could not be cloned -- but a month after his talk, they were! The lesson from this is that we do not know what the cloning future holds and that it is risky to make categorical statements in this field (or any other!).
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