MEDICINE'S GENETIC HORIZONS*

Excerpt

For something over 500,000 years there have existed on this earth species of man with a cranial capacity approaching that of modern man. For at least 99% of that time span the generation-to-generation rate of cultural change has been, viewed from our current vantage point, almost unbelievably slow. By cultural change I mean nothing more profound than changes in the circumstances of day-to-day living. It took something like 75,000 years for the rough Chellean hand-axe to be replaced by the more even, symmetric Acheulian hand-axe in Western Europe during the Pleistocene. Then, starting with the Agricultural Revolution, and accelerating with