MERCHANTS OF MORTALITY

Immortality? Perhaps not, but life extension is already a reality.

Science writer Hall (A Commotion in the Blood, 1997, etc.) explores just how much more time we can expect. He begins with Leonard Hayflick, who in the late 1950s found that living cells lose their ability to keep dividing after about 50 generations. There was soon evidence tying this “Hayflick limit” to telomeres, repetitive DNA sequences at the end of chromosomes that grow shorter with each division. On the reasonable theory that preserving these sequences might help stave off senescence, biochemists began searching for the enzyme that creates telomeres. Entrepreneurs were close on their heels, among them Michael West, who has been a highly visible pitchman for the effort to extend human life through biotechnology. His early company, Geron, was founded to explore the potential of telomerase to slow aging; later, the company looked at its application to cancer. When telomere research was slow to bear fruit, West and his colleagues moved on to newer and more promising areas, notably the undifferentiated cells that form early in the growth of an embryo. These stem cells have the ability to mutate into any bodily tissue, from bone to nerve to heart muscle; their potential for medical use may be boundless. But their derivation from embryonic material set off a raging political debate, culminating in the Bush administration's perhaps ill-advised decision to restrict stem-cell research to those lines already in existence as of August 2001. Hall gives the reader a fair summary of the arguments on all sides, while making clear his own view that politicians ought to tread very carefully when intruding into scientific questions that not even the scientists have entirely sorted out.

A carefully documented examination of how society deals with life-and-death matters.