Figure 18

We cannot even imagine what opportunities our comprehension of DNA and our ability to modify the molecule will present in the distant future. Possibilities range from significant lengthening of the human life expectancy to the creation of new life-forms. Deciphering the DNA structure has already led to an understanding of the genetic basis of diseases, which has revolutionized the search for treatments. The genome era has heralded previously unimaginable achievements in forensic science. For instance, following the deaths of five people from anthrax-laced letters in 2001, the US Federal Bureau of Investigation decided to sequence the entire microbial genome of the strain used in the attacks (5.2 million base pairs). That effort eventually led investigators to an army lab that was the most likely source of the strain. At the same time, with the exposition of the structure of DNA and of proteins, the question of the origin of life has become even more intriguing and potentially answerable. But the inquiries have penetrated to an even more fundamental level than the purely biological: Where did the building blocks of life, those information-carrying, replicating molecules, come from? And on the physics side, going back to earlier origins yet, how did the hydrogen atom, which was so crucial to Pauling’s hydrogen bond, appear in the universe? And what about the heavier elements that are so essential for life, such as carbon, oxygen, nitrogen, and phosphorus?

The Russian-born physicist George Gamow participated in the early attempts to understand how the four bases in DNA could control the synthesis of proteins from amino acids. Gamow was shown a copy of the paper by Watson and Crick on the genetic implications of their model while visiting the Radiation Laboratory at Berkeley. Excited, he started thinking about it as soon as he returned to his department at George Washington University, swiftly dispatching a letter to Watson and Crick. He started apologetically—“Dear Drs. Watson and Crick, I am a physicist, not a biologist”—but soon came to his main point: Could the relationship between the four letters corresponding to the bases in DNA, and the twenty amino acids in proteins, be solved as a problem in pure numerical cryptoanalysis? While Gamow’s mathematical solutions eventually turned out to be wrong, they did help in framing the questions of biology in the language of information.

About five years earlier, Gamow was involved in solving an even more fundamental problem: the cosmic origin of hydrogen and helium. His solution was truly brilliant. It did not explain, however, the existence of all the elements heavier than helium. This formidable task was left to another astrophysicist and cosmologist: Fred Hoyle. On one hand, Hoyle concerned himself with the evolution of the universe as a whole, and on the other, with the emergence of life within it. He was at the same time one of the most distinguished and one of the most controversial scientists of the twentieth century.