STOCKHOLM, Oct. 4 -- American scientist Roger Kornberg won the 2006 Nobel Prize in chemistry on Wednesday for his work on describing gene copying in cells.

His father, Dr. Arthur Kornberg, was the 1959 winner of the Nobel Prize in Medicine.

The Kornbergs are the sixth set of fathers-and-sons to win Nobel prizes, while one father and daughter -- Pierre Curie and Irne Joliot-Curie, won the Nobel prize in physics and chemistry respectively.

Irne's mother, the famous Marie Curie, who was married to Pierre, also won two Nobel Prizes for chemistry and physics.

Danish scientist Niels Bohr won the Nobel Prize in physics in 1922 and his son Aage Bohr shared the physics award with American Ben Mottelson in 1974.

(Agencies)