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Sixty years after the discovery of DNA's spiraling, ladder-like structure first hinted at the mechanism by which life copies itself, one of the Nobel Prize medals honoring this achievement is up for sale.

Three men who played crucial roles in deciphering DNA's double helix in 1953 later received the Nobel Prize in Physiology or Medicine. The family of one of those men, Francis Crick, plans to sell his medal, the accompanying diploma and other items at auction with a portion of the proceeds set to benefit research institutions in the United States and the United Kingdom.

"It had been tucked away for so long," said Kindra Crick, Francis Crick's 36-year-old granddaughter, of the medal. "We really were interested in finding someone who could look after it, and possibly put it on display so it could inspire the next generation of scientists." Francis Crick passed away in 2004 at the age of 88.

The value of Nobel gold
There is little precedent for this sale. Nobel medals appear to have changed hands publicly in only a couple of instances. This particular medal, like others made before 1980, is struck in 23-carat gold, and recognizes a particularly high-profile accomplishment in biology, one fundamental to modern genetics.

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The auction house handling the sale, Heritage Auctions, has valued the medal and diploma at $500,000, which is "an educated guestimate," said Sandra Palomino, Heritage Auctions' director of historical manuscripts. Estimates by Heritage's in-house coin experts went as high as $5 million, Palomino said. [See Photos of Crick's Medal & Other Auction Items]

The April auction will also include Crick's award check with his endorsement on the back, the scientist's lab coat, his gardening logs, nautical journals and books. Separately, the family hopes to sell a letter Crick wrote in 1953 to his then-12-year-old son Michael, who is Kindra's father, describing the discovery's meaning. The auction house Christies, which Kindra Crick said is handling the sale, declined to confirm plans to sell this letter.

Out of the box
The medal was not displayed much within Crick's family. Kindra remembers that the Nobel, which she has yet to see herself, was locked in a room with her grandfather's other awards and other family heirlooms after he moved to California at the age of 60. After the scientist's wife, Odile, passed away in 2007, the medal was sequestered in a safe deposit box. Crick's children, including Kindra's father, Michael, attended the award ceremony in 1962, but saw almost nothing of the medal afterward.

Kindra plans to get a look at the medal before the auction.

"My grandfather was not the type of personality to show off," she said. "His conversation tended to be on what's next as opposed to reminiscing about the past … I guess he always thought there was more to come."

Crick's family hopes to see the medal displayed publicly after its sale; however, Kindra Crick acknowledged that a public auction offered no guarantee a buyer would display the award. But she is optimistic, saying those individuals or institutions with enough interest in science to bid on the medal are also likely to display it publicly. [Creative Genius: The World's Greatest Minds]

Crick's family and Heritage Auctions plan to donate a portion of the proceeds from the sale of the medal and the other items to The Francis Crick Institute, a medical research institute scheduled to open in London in 2015. A portion of the proceeds from the sale of the letter will go to benefit the Salk Institute in California, where Francis Crick studied consciousness later in his career, Kindra said.

Sixty years later
On Feb. 28, 1953, according to legend, Crick and his colleague James Watson announced that they had discovered the "secret of life" in a pub frequented by other Cambridge University scientists.

This followed Watson's realization that the molecular bonds between the two types of base pairs in DNA — adenine with thymine and cytosine with guanine — were identical in shape, suggesting a double helix with complementary halves, Watson recounts in "The Annotated and Illustrated Double Helix" (Simon & Schuster, 2012).

This discovery was the result of a combination of approaches; Watson and Crick built models, trying to determine how the molecules known to make up DNA (deoxyribonucleic acid) fit together. Meanwhile, two of their colleagues, Maurice Wilkins and Rosalind Franklin, created images by bouncing X-rays off DNA crystals.

One of Franklin's images, called Photograph 51, provided key evidence of a helical shape.

Crick, Watson and Wilkins received the Nobel Prize in 1962. Franklin did not because she passed away in 1958, and the Nobel Prize is not awarded posthumously.

Form means function
In the years prior to this discovery, scientists knew of the existence of DNA (a type of molecule known as a nucleic acid), but not what it looked like or its true function. They also knew genes carried traits from generation to generation, but many scientists believed genes to be made of proteins, said Jan Witkowski, executive director of the Banbury Center at Cold Spring Harbor Laboratory in New York.

The discovery of the structure of DNA was key to understanding the molecule's function as the code for genes. Watson and Crick understood this, but when they described their discovery in a paper in the journal Nature in April 1953, they wrote coyly of the implications: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for genetic material." [Code of Life: Photos of DNA Structures]

However, in the letter to 12-year-old Michael, dated March 19, 1953, Crick drew a diagram spelling out the scientists' theory of how DNA replicated: the double helix and its base-pair rungs separated to create templates for new strands.

"In other words, we think we have found the basic copying mechanism by which life comes from life," Crick wrote to his son. The scientists signed the letter, which appears in "The Annotated and Illustrated Double Helix," "lots of love, Daddy."

A geneticist himself, Witkowski lists the discovery of the structure of DNA as one of the three most pivotal accomplishments in biology, along with Charles Darwin's theory of evolution by natural selection and Gregor Mendel's principles of inheritance.

"Of course, it wasn't so much what each discovery was in itself, but what avenues it opened up and what it led on to," said Witkowski, who with Alexander Gann, edited the "Annotated and Illustrated Double Helix."

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