Watson is the first living recipient to auction off his Nobel medalRussia's richest man has revealed that he bought US scientist James Watson's Nobel Prize gold medal, and intends to return it to him.
Steel and telecoms tycoon Alisher Usmanov said Mr Watson "deserved" the medal, and that he was "distressed" the scientist had felt forced to sell it.
The medal, awarded in 1962 for the discovery of the structure of DNA, sold for $4.8m (£3m) at auction.
The medal was the first Nobel Prize to be put on sale by a living recipient.
The 1962 prize was awarded to Watson, along with Maurice Wilkins and Francis Crick, with each receiving a gold medal.
Mr Usmanov described Mr Watson's situation as unacceptableMr Watson, 86, has said he planned to donate part of the proceeds to charities and to support scientific research.
In an interview with the Financial Times recently, Mr Watson said he had been made to feel like an "unperson" since a Sunday Times interview seven years ago in which he linked race to intelligence.
Mr Usmanov said in a statement that he was the anonymous telephone bidder who bought the medal at a Christie's auction last week.
"In my opinion, a situation in which an outstanding scientist has to sell a medal recognising his achievements is unacceptable," he added.
"James Watson is one of the greatest biologists in the history of mankind and his award for the discovery of DNA structure must belong to him."
Mr Usmanov, said by Forbes magazine to be worth $15.8bn, is a major shareholder in Arsenal football club and was named Britain's wealthiest man in the Sunday Times rich list for 2013.