The Secret of Life

(9 of 9)

Geneticists are so confident of their new science these days that most of them do not dodge questions about the origin of life on earth. The first living things, they say, were probably crude, simple versions of DNA. They floated in an ocean, or perhaps some smaller body of water, and floating around them were all sorts of organic molecules that had been formed by chemical chance. At long intervals the crude ancestral DNA found and seized some molecule that it wanted. When it had caught enough smaller molecules, it was ready to divide into two identical parts.

This would be true growth, say the geneticists, and evolution would soon improve the original breed. DNA would eventually wrap itself in cells and retire to their nuclei to give orders. Cells would later band together into multicelled animals, but they would not escape the commands of the DNA within them. Samuel Butler wrote: "A hen is only an egg's way of making another egg." Geneticists like to make this remark more general: "All plants, and animals and humans," they say, "are DNA's way of making more DNA."

Genetics & Bomb Tests. A part of the public seems to think that the chief concern of genetics is the hereditary damage that may or may not be done by the radioactive fallout from nuclear bombs and bomb tests. Geneticists insist that this matter is not a central part of their science, but none of them takes the potential effects of fallout lightly. They have spent their working lives with experimental organisms deliberately deformed by radiation. They know how recessive damaged genes persist unnoticed for many generations, only to appear (and perhaps to kill or cripple) when two of them meet in the same fertilized egg. They know that some damaged genes in humans have bad effects so subtle that they are hard to measure or count. They suspect that radiation damage to genetic material may have many unknown relations to cancer. Most of them say emphatically that the less radiation on the loose, the better it is for the world.

Beadle does not take an extreme position. "As a geneticist," he says, "I am prepared to say that fallout is biologically harmful and that we must therefore recognize a moral responsibility to humanity to reduce it to the lowest possible level." He is not sure "whether nuclear-weapons testing has a military or other benefit that outweighs the biological harm." But, like other geneticists, he knows too much to be indifferent to the problem.