Word: helix
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Dates: during 1950-1959
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...Chemist Linus Pauling, who won a Nobel Prize for his work on molecular structure, reported that the DNA molecule has a helical (spiral-staircase) structure. Later that year, James D. Watson and Francis H.C. Crick in England went a step farther. DNA, they said, is a double helix with two spirally rising chains of linked atomic groups and a series of horizontal members, like steps, connecting the two spirals. This molecular model, deduced mostly from X-ray diffraction photos, seemed complex and unlikely, but geneticists rejoiced when they heard about it. It was just what they" needed to explain many...
Here, the geneticists now believe, lies the high command of growth and reproduction. Double-helix DNA molecules, thousands of turns long and arranged by thousands in each chromosome, can carry a vast amount of coded information. They may very likely carry enough to determine whether a fertilized egg grows into a clam or an elephant. When chromosomes replicate during cell division, the DNA molecules that they contain presumably replicate...
...emergency food by the Japanese during World War II. When Clausen heard that 5,000 Gonaxis snails had been rounded up on Agiguan for anti-pest assignments on other islands, he put in a bid for a consignment of 200. Currently being fed on a diet of Helix snails in the university laboratories, they will be turned loose in the spring in selected orange and lemon groves from Santa Barbara to San Diego...
Natural Balance. Similarly, the Helix snail, presumably imported from Europe, did not become a hazard to citrus groves until it reached California. In effect, what the biologists hope to do is restore a natural balance, which was upset when the Helix left home...
...keeping native California snails in check. Why import a foreign variety? In reply, Clausen points to the fact that California snails have generally stuck to wild areas, and presumably could not be coaxed into orchards. More over, says Clausen, he does not fear that the Gonaxis will devour the Helix and turn to other food. Long before that happens, the law of supply and demand will take over, freezing the population of both hunter and hunted at a safe level...