Using evolutionary biology, scientists have been able to debunk the long-held theory that the sexually voracious Wife of Bath was actually so outrageous.

Biologists at Cambridge University have used a system developed for tracing the origin of the species through their DNA to work out which of the 58 surviving versions of The Canterbury Tales are closest to the original, which no longer exists.

DNA tests show the Wife of Bath to be more demure

Some depict the wife as coarse and with an indiscriminate sexual appetite, but researchers say they can now restore her to the personality they believe Chaucer intended.

The most authentic manuscripts still paint her as outrageous, but with hankerings after respectability.

The infamous passage about her appetite for all men "were he short or long or black or white", no matter "how poore" or of "what degree", was probably excised by Chaucer and replaced by scholars later, the scientists have discovered.

The results of the research - published in the scientific journal Nature - found evidence for believing that Chaucer's own copy was not a completed single text but a working draft.

The researchers, led by Dr Christopher Howe, wrote: "In time, this may lead editors to produce a radically different text of The Canterbury Tales."

Dr Christopher Howe and DR Peter Robinson explain how they made the breakthrough

Speaking on Radio 4's Today programme, one of the literary experts who worked on the project, Dr Peter Robinson, said the research made the Wife of Bath a different person.

"It stresses her desire for social and economic dominance rather than her sexual aggression," he said.

Dr Howe's team worked with manuscript experts from De Montfort University in Leicester who are investigating the origins of Chaucer's works.

They used the latest computerised techniques normally used by biologists to reconstruct the evolutionary trees of different species from their DNA.

Early hand-copied manuscripts often contain duplicated mistakes and variations.

By comparing the similarities and differences of a number of texts, scientists are able to reach conclusions about what an original copy was like, even if it has been lost.

Family trees

Until now, the technique, known as 'stemmatics', has been a laborious manual process only feasible for a few short manuscripts.

But Dr Howe realised it had much in common with the techniques used by evolutionary biologists to track different species' family trees.

He and his team concentrated on The Wife of Bath's Prologue to produce a computer-generated family tree showing the relationships between the 58 different 15th century versions of the story.

A number of manuscripts formed groups which could be traced back to distinct common ancestors.

One particular group appeared to go back further than the others to a point probably close to the missing original.

Yet these manuscripts had mostly been ignored by scholars.

Dr Robinson added that the work had given the team a "radically more efficient" way of discovering the early history of the Tales.

"It has already suggested vital new approaches to long-unsolved problems, which will bring us much closer to understanding what Chaucer left behind him at his death."