Left Handed
© The Independent, UK
100,000 people had their genes sequenced to determine handedness.
Left-handed people may be even more unique than first thought, thanks to a study that has linked one rare condition with another.

100,000 people had their genes sequenced to determine handedness, and it seems that a condition called situs inversus may be able to provide clues behind what makes people use their left hand instead of the right.

One in 20,000 people are affected by the condition which mirrors the major organs from their major positions: for instance the heart would be on the right side of the body instead of the left.

Human geneticist Silvia Paracchini and her team from the University of St Andrews found that the part of the genetic code which is abnormal in people who have situs inversus is the same that affects handedness.

Paracchini said: "The reason why it fascinates us is that we don't really understand it. It's fascinating but also puzzling.

"There must be an evolutionary advantage [to being right-handed]."

While 25 per cent of all left handedness can be linked by a person's genes, the other 75 per cent is still yet to be fully explained.

Just 12 per cent of the world's population is left-handed, with twice as many male left-handers as women, but 30 per cent of people can switch hands during some tasks.

Right handed people reportedly earn 12 per cent more over their lifetimes than lefties, while Harvard economist Joshua Goodman claimed that "lefties have more emotional and behavioural problems".

However, there are plenty of famous left-handers to boast about.

Leonardo Da Vinci, Pierce Brosnan, Nicole Kidman, Marilyn Monroe, Lewis Caroll, Spike Lee, David Bowie, Kurt Cobain, Annie Lennox, Jimmi Hendrix, Ross Kemp, Julius Caesar, Neil Armstrong, Winston Churchill, Babe Ruth, Noel Gallagher and Bart Simpson were/are all left-handers.