The Nobel Prize gold medal awarded to the U.S. scientist and co-discoverer of DNA, James Watson, sold at auction on Thursday for more than $4.7 million, smashing the world record price for any Nobel prize.

The medal, which Christie's auction house had estimated would sell for anywhere from $2.5 million to as much as $3.5 million, was the first Nobel put on sale by a living recipient.

Christie's did not disclose the buyer, who was bidding via telephone and paid $4,757,000, including commission.

The price and record "demonstrate the growing strength in the market for the iconic pieces related to the early understanding and development of the implications of DNA and its growing relevance today," said Francis Wahlgren, international director of books and manuscripts at Christie's.

Watson, along with Francis Crick and Maurice Wilkins, unraveled the double-helix structure and function of deoxyribonucleic acid (DNA) in Britain in 1953 in a discovery that heralded the modern era of biology.

The scientists received the Nobel Prize for medicine in 1962 for their groundbreaking work in genetics. Watson, 86, said he planned to donate part of the proceeds to charities and to support scientific research.

A letter by Crick to his son sold for $6 million in 2013, setting the world record for any letter sold at auction. The missive, in which Crick outlined the structure of DNA shortly before the discovery was published, sold for more than three times the estimate.

Crick's Nobel medal fetched $2.27 million when it was auctioned last year.

A 1936 Nobel Peace Prize medal sold for $1.1 million last year. It had been awarded to Carlos Saavedra Lamas, foreign minister of Argentina, for his part in ending the Chaco War between Paraguay and Bolivia, and for his work on a South American antiwar pact signed in 1933.

(Reporting by Chris Michaud; Editing by Clarence Fernandez)