The study of DNA in heredity and disease has led to a great many
heady scientific discoveries and, ironically, to some humbling acknowledgments
of ancient medical wisdom.
Scientists discovered nucleic acids, the general chemical building
blocks of DNA (deoxyribonucleic acid) and genes, in the 1890s.Within
several decades, biochemists and biologists had gained an impressive
understanding of how nucleic acids were involved in heredity, and by
1950 experiments with bacteria had proven that DNA transmits inherited
traits from one generation to the next.
Perhaps the single most dramatic event to ignite the imagination
and enthusiasm of biologists was the 1953 discovery by James Watson
and Francis Crick of the double-helix structure of DNA. All that
remained, or so it seemed at the time, was to decipher and describe the
genetic code in terms of its four-letter chemical alphabet.
But unraveling the details of DNA and its role in health and disease
has turned out to be a far more complex and, at times, vexing process.
As it turned out, the new millennium coincided with the complete
decoding of the human genome, and this catalog of all human genes has
led to many new insights into the function of DNA. Unfortunately, the
promise of turning these discoveries into practical ways of preventing
and treating disease has so far been disappointing. Cardiovascular diseases
remain the leading cause of death in the United States and most
of the developed world, while the scourge of cancer continues to take
its relentless toll despite minor advances in treatment and prevention.
Gene therapy has proven dangerous and difficult and has had few significant
successes. Despite our current understanding of cancer-causing
oncogenes and the details of how genes function, researchers have
devised few new and effective therapies for cancer patients.