LIFE ITSELF

The dean of molecular biologists is now trying his hand at popularization--but this is not DNA history (viz., Mahlon Hoagland, below) or personal history. Rather, Crick is tentatively setting forth a theory of life's origins that he and colleague Leslie Orgel have concocted in recent years: directed panspermia. The idea is that life on earth may have come about through the introduction of selected microorganisms some four billion years ago by some evolved civilization elsewhere in the galaxy. Crick admits that there is precious little evidence for the theory--but the same is true of the prevailing concept of a prebiotic soup and an early ""reducing"" atmosphere on earth. (In that hypothesis, electrical storms and strong tides might have provided the spark and the stirring that led to the production of macromoleculea--some of which, in time, might have replicated.) Fortunately, such theories are a springboard for explaining much that Crick understands very well: DNA, RNA, microorganisms, living systems in general. He must also summarize cosmological theories on the origins of the universe and the solar system, so that a good hunk of the book is popular astronomy. Crick as popularizer is the soul of patience, perhaps too patient: sometimes he seems the earnest schoolteacher repeating himself to make sure the message is understood. However, he does come up with some marvelous Crickian phrases: RNA and DNA, we are told, are ""the dumb blondes of the biomolecular world, fit mainly for reproduction (with a little help from proteins)."" We also learn that ""the two chains of DNA are like two lovers, held tightly together in an intimate embrace, but separable because however closely they fit together, each has a unity which is stronger than the bonds which united them."" So what about directed panspermia? Since Crick himself is less than convinced, he does not quite persuade the reader of its intrinsic rightness. But he does make a good case for caring about such matters, listening for Them out There, and, perhaps, aiming our own directed panspermia toward other life sites. The quintessence of idle curiosity--and because it's Francis Crick, definitely worth listening to.