Image copyright Getty Images Image caption Watson is the first living recipient to auction off his Nobel medal

Prof James Watson is to auction off the Nobel Prize medal he won for the discovery of the structure of DNA.

The auctioneer says the medal is the first to be auctioned by a living recipient and could fetch between $2.5m (£1.6m) and $3.5m (£2.2m).

The 1962 prize was awarded to Watson, Maurice Wilkins and Francis Crick, with each receiving a gold medal.

The auction includes papers belonging to Watson, including handwritten notes for his acceptance speech.

Christie's estimates these at between $300,000 (£190,000) and $400,000 (£254,000)

The discovery of the structure of DNA - which encodes the instruction booklet for building a living organism - was made by Watson and Crick, using experimental data that had been gathered by Maurice Wilkins and Rosalind Franklin.

Prof Watson said part of the proceeds would go to the University of Chicago, Clare College at Cambridge University, Cold Spring Harbor Laboratory, Long Island Land Trust and other charities.

Francis Crick's Nobel medal sold for $2.2m last year. He died in 2004.