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Episode 1 : The Secret of LifeEpisode 1 : The Secret of Life

Special Report
DNA: The Ugly Duckling of Genetics, by Magdalena Eriksson: Page 1 of 2
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We probably don't have a gene for curiosity, but our inquisitive nature still seems encoded in the combined messages of our genes. The progress of man and our intellectual history -- from painting on cave walls to travels in space -- are all spurred by our irresistible desire to understand the unknown. And for many of today's researchers, the great scientific frontier involves the mining of the codes of genomes.

When James Watson and Francis Crick took up the quest of determining the three-dimensional structure of DNA in the early 1950s, they sat down as uninvited guests at a set table. The two, at the time junior, scientists did not hesitate to grasp for data already obtained by other scientists -- sometimes even picking from their plates. Studying Rosalind Franklin's x-ray crystallography of the DNA molecule without her knowledge, for instance, was a vital step toward their discovery. What Watson and Crick brought to the table was primarily their strong conviction that the DNA structure would be of great importance. And so they succeeded in connecting pieces, old and new, from friend and from foe, and in 1953 delivered the structure of a double helix DNA molecule.

Test tubes
What Watson and Crick brought to the table was primarily their strong conviction that the DNA structure would be of great importance.

Watson and Crick's accomplishment was in some measure built on the work of their contemporary DNA researchers, but it was also a coalescence of years of work in a number of scientific fields. In 1926, the theoretical physicist Erwin Schrödinger had introduced an equation that describes the behavior of matter, which in practice only works for only very small systems, an isolated atom or molecule at a time. In the 1940s, Schrödinger's interests had expanded to include biology. He proclaimed that living and non-living matter all obey the same laws of physics and chemistry, and proposed that living organisms should be treated in terms of molecular and atomic structure. In 1944, he challenged the biological-science community by postulating the existence of a similar description, a "hereditary code-script," in his book WHAT IS LIFE.

Long before anyone attempted to describe life in terms of chemistry and physics, biology was developing from the observation of animals and plants in nature. The work of two early pioneers had made the existence of a hereditary code-script logical.

In 1859, Charles Darwin had proposed his principles of evolution and in 1865 Gregor Mendel had discovered the basic laws of heredity, but neither of them addressed what actually directed the systems they studied. The actual carrier of the rules of evolution and heredity, which must be contained somewhere, in animals as well as in plants, were never found by these early pioneers.

By 1869, an important clue leading to the location of these carriers was in the making, as the Swiss scientist Friedrich Miescher isolated what he termed "nuclein" while working at a local hospital in Tübingen, Germany. There, he found the mysterious substance in pus-soaked bandages, rich in white blood cells. Miescher learned that the only source for nuclein was chromosomes, which he realized was a significant discovery. Hence he supported the "chemical heredity theory," which contends that our basic biological information is passed from generation to generation and is stored in chemical substances in our cells.

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Francis Crick
Francis Crick
James Watson
James Watson
Rosalind Franklin
Rosalind Franklin

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