Francis Crick & James Watson: DNA

Francis Crick and James Watson, discoverers of the DNA molecular structure. One of the most important biological discovery in the 20th century.

Francis Crick was born on June 8, 1916 in Northampton, England, into a middle-class family. He began doing science experiments in his home when he was ten years old. He graduated with a degree in Physics from University College in London.

James Watson was born on April 6, 1928 in Chicago, and at the age of 15 enrolled in Chicago University and majored in zoology. He received a Ph.D. in genetics from Indiana University, when he was 22 years old. In 1951, he joined Francis Crick at Cavendish Laboratory in Cambridge, England. He was only 23 years old when his greatest discovery was made.

Linus Pauling's work on the structure of biomolecular and hydrogen bonding formed the basis of Crick and Watson's study of DNA. Speaking of Pauling's work, Watson stated,

"In 1931, when he was 30, Linus Pauling knew he was the world's best chemist. Ten years later his peers agreed. By then, The Nature of the Chemical Bond (1939) was already on its way to becoming the most influential chemistry book of the century. His biggest biological success came from his 1951 proposal of the alpha-helical fold for protein molecules, which everybody else thought were too large and complex to study. Then, unexpectedly, he struck out when he proposed an implausible, three-chain helix for DNA. Several months later, in Cambridge, England, Francis Crick and I, apprehensive that Linus might bat again, found the double helix. Why Linus failed to hit this home run will never be known. I most remember Pauling from 50 years ago, when he proclaimed that no vital forces, only chemical bonds, underlie life. Without that message, Crick and I might never have succeeded."

In 1953, James Watson and Francis Crick discovered the molecular structure of DNA. Underplaying their discovery, in a letter to scientist Max Delbruck, James Watson wrote,

"In the next day of so, Crick and I shall send a note to Nature proposing our structure as a possible model. If by chance it is right, then I suspect we will be making a slight dent into the manner in which DNA can reproduce itself. I prefer this type of model over Pauling's which if true, tells us next to nothing about the essence of DNA reproduction."

A model of the structure resembled a twisted rope ladder. They proposed that the DNA molecule consisted of two spirally wound, helical chains. They demonstrated how genetic information is passed on through DNA in the genes. In 1968, Watson published The Double Helix, a portion of it reads,

"Science seldom proceeds in the straightforward logical manner imagined by outsiders. Instead its steps forward (and backward) are often very human events in which personalities and cultural traditions play major roles."

In 1962, Crick, Watson, and their associate, Maurice Wilkins, were awarded the Nobel Prize for their work. Crick explained their discovery on the day they received the award:

"DNA is a polymer. That is to say it has a regular, repeating backbone with side groups called "╦ťbases' projecting at regular intervals. However all the bases are not the same, there are four kinds of them and the genetic information is conveyed by the precise order of the different sorts of bases along the DNA. In other words, the genetic message is written in a language of four letters. Incidentally, the total length of the message for man is not short, it is probably more than a thousand million letters long."

In 1968, Watson became director of the molecular-biology lab at Cold Spring Harbor, New York and in 1988 became head of the United States Human Genome Project. In 1977, Crick began brain research at the Salk Institute and is now a professor at the Salk Institute for Biological Studies in LaJolla, California.

As a result of their discovery, scientists have been able to identify that the causes of some illnesses are genetic. Some of the most recent breakthroughs are the use of DNA in crime cases, the determination of blood relatives and the cloning of Dolly the sheep. According to John Maynard Smith, Emeritus Professor of Biology at the University of Sussex,

"To discover the chemical basis of heredity is profoundly important when you bear in mind that the whole not only of evolution but the whole of development, the whole of biology, depends on that property of heredity. To say that you now actually know how it works, is profoundly important."

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