Why Are Some People Left-Handed? Science Has A Rather Unusual Explanation Why 10 Percent Of The World’s Population Prefers The ‘Other’ Hand

The left-handed people aren’t uncommon, but their plight is more than noticeable in this world dominated by the right-handed people. Now science has attempted to explain why almost 10 percent of the world’s population is left-handed.

One in 10 people in the world have been observed to be left-handed, nicknamed lefties. Interestingly, this 10 percent ratio is fixed the world over, giving credence to the idea of a genetic basis for the population’s hand preference. In fact, several studies predominantly conducted on twins have shown that 25 percent of the handedness can be traced back to the genes. The percentage may be lower than expected, but it shows surprising consistency, revealed human geneticist Silvia Paracchini from the University of St Andrews in Scotland.

Till date scientists had been unable to locate the gene that governed or influenced the preference of the hand. But surprisingly, the researchers realized that the DNA that influences handedness is the same that determines our body’s asymmetry, shared Paracchini,

“We look symmetric, but if we look inside at our organs there’s lots of asymmetry.”

People’s preference of the hand may lie in the rare genetic condition called Situs Inversus. Affecting nearly 1 in 20,000 people – including Spanish-born singer Enrique Iglesias – people with Situs Inversus have their major organs in the opposite direction than what is normally observed. Say for example, the heart would be tilted to the right or the gall bladder and liver could be on the left side instead of their general location to the right.

Paracchini and her team discovered that the part of the genetic code that’s abnormal in people with Situs Inversus is the same part that influences handedness. More notably, as a result of this asymmetry, left-handed people also have larger corpus callosum – a thick band of nerve fibers in the brain that divides the left and right hemispheres of the cerebellum.

Though the world is a lot less friendly to left-handed people with many forced to use their right hand during their childhood, it is they who have a slight advantage over their right-handed people, shared Paracchini.

“Left-handed people have advantages in some sports and they can be more skilled in certain tasks as their brains are more plastic.”

Interestingly though, the slightly more flexibility of the brain is because of the constant challenges left-handed people face in this predominantly right-handed world.

[Image Credit | WiseGeek, Loon Pond]