A treasure trove of letters that lay buried in boxes for decades has shed light on the race to decipher the structure of DNA, the British journal Nature says on Thursday.

The correspondence exposes some of the tensions among the scientists who sought to balance profession rivalry, suspicion and friendship in their quest for biology's Holy Grail.

"Strained relationships and vivid personalities leap off the pages," the report says.

Francis Crick, James Watson and Maurice Wilkins were awarded the Nobel Prize in 1962 for determining the structure of the chemical code for life: a dazzlingly simple double-helix corkscrew bound by pairs of chemical "rungs."

Publication of their work in 1953 was the starting gun for the genetic revolution which has shaken up medicine, anthropology, agriculture and sociology and many other fields.

The letters, found in the archives of another molecular biologist, add details to the DNA story, spicing it with the tones of turf battles, misunderstandings and hurt egos.

"We are really between forces which may grind all of us into little pieces," Wilkins confides to Crick at one point, dismayed at the power games unfolding in the background.

Crick was a Briton who had wandered languidly down several paths of investigation into DNA before teaming up with James Watson, a brash young American, at Cambridge's famous Cavendish Laboratory.

They struck up an instant rapport, welded by the belief that an enigmatic molecule called deoxyribonucleic acid (DNA) - and not proteins, as was then commonly thought - held the genetic data that was handed down from generation to generation.

But their somewhat cavalier style, and taste for ideas that they explored with cardboard models rather than the hard graft of lab work, cast the pair as mavericks.

They were initially assigned to crack open DNA, were then hauled off the job and finally were put on it again in the fear that the American chemist Linus Pauling was about to get there first.

Wilkins worked in King's College London with a fellow Briton, Rosalind Franklin.

Like Wilkins, Franklin was a nuts-and-bolts experimentalist, and it was her X-ray diffraction images of molecules that unlocked the theoretical breakthrough.

The letters point to Wilkins' irritations as Watson and Crick tried to poach a look at the research at King's.

And they highlight the poisonous relationship between Wilkins and Franklin, caused by a misunderstanding by their boss as to who had been named in charge of DNA research at their lab.

It was Wilkins who - behind Franklin's back, according to some accounts - showed Watson an image, now immortalised as Photo 51, that, the young American quietly noted, clearly showed a double helix.

"I hope the smoke of witchcraft will soon be getting out of our eyes," Wilkins writes in relief, just before Franklin headed out of the door to a job in another laboratory.

Franklin died of cancer in 1958, which meant she was ineligible to be considered for the 1962 Nobel. But some feminists contend her career was truncated by a male elite and her great contribution has never been fully acknowledged.

The new haul comprises dozens of letters to and from Crick that got mixed up with the documents of Sydney Brenner, himself a molecular biologist and Nobel laureate, who shared an office with Crick for many years.

The letters have been found by two professors at Cold Spring Harbor Laboratory in New York, to which Brenner donated his archive and where Watson today is chancellor emeritus.

The correspondence shows Wilkins' "tortured soul," say the finders, Alex Gann and Jan Witkowski, in their Nature article.

"Maurice Wilkins on the one hand wanted to be open," said Witkowski.

"He believed science should be open and was all in favour of cooperation, the exchange of ideas and data. But on the other hand, he was also mindful of his own career: he knew he had to get results and publish papers."