James Watson helped to discover the helical structure of DNA. Credit: Daniel Mordzinksi/AFP/Getty

James Watson, the molecular biologist who has become nearly as famous for his unfiltered, off-colour remarks as for his role in the discovery of the double-helix structure of DNA, has achieved another milestone. On 4 December, he became the first scientist to auction his own Nobel prize medal.

The anonymous buyer paid US$4.76 million, including the buyer's premium that goes to the auction house, participating by telephone in the sale held at Christie's auction house in New York City. That is the highest price ever paid for a Nobel medal, and far outstripped predictions that Watson's prize would sell for$2.5 million to $3.5 million. The sale comes more than a year after the family of Francis Crick, who shared the 1962 Nobel Prize in Physiology or Medicine with Watson, sold his medal for$2.27 million. "I'm very pleased," Watson said after the auction. "I wanted to be at least equal to Crick, but this exceeded his."

Whereas Crick remained a relatively private person until his death in 2004, Watson is a notorious rabble-rouser whohas not been shy about voicing his views on race and gender.

Watson's Nobel prize. Credit: Christie's Images Ltd

In 2007, he was suspended from his post as chancellor of the Cold Spring Harbor Laboratory in Long Island, New York, after controversy erupted over his suggestion to The Sunday Times that black people are not as intelligent as white. “All our social policies are based on the fact that their intelligence is the same as ours — whereas all the testing says not really," he said. Watson retired from the laboratory shortly after.

Watson told Nature that his motivation for selling the medal is a chance for redemption. He plans to donate some of the proceeds to Cold Spring, where he remains chancellor emeritus — receiving a $375,000 base salary in 2012, according to the laboratory's latest publicly available tax filings. Watson says that he will also donate to University College Cork in Ireland to help to establish an institute dedicated to the British mathematician George Boole. "I'm 52% Irish," Watson said by way of explanation. He previously told the Financial Times, perhaps in jest, that he might also buy himself a David Hockney painting. In addition to the medal, Watson auctioned off notes from his Nobel acceptance speech — scribbled on stationery from the Grand Hotel in Stockholm — and lecture. The speech sold for$365,000 and the lecture for \$245,000.

After the auction concluded, the 86-year-old Watson ambled to the front of the room as friends and colleagues snapped photographs. Watson's Nobel medal was removed from a white lacquer case and placed in his hands one last time.

"That's not yours any more," someone shouted at him. No — but he does have a replica at his home.