Benedict XVI chose Werner Arber, a Swiss molecular biologist who shared the Nobel Prize for Medicine in 1978, as president of the Pontifical Academy of Sciences.

A Vatican spokesman, Father Ciro Benedettini, said it is the first time a non-Roman Catholic has led the academy in its four centuries of history.

The academy help pontiffs understand scientific advances in fields ranging from genetics to nuclear physics.

Mr Arber became a member in 1981.

Other non-Catholics who have been prominent academy members, but not president, include Rita Levi Montalcini, an Italian Jew and 1986 Nobel winner for medicine.

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