Right/Left Handedness

I was in a discussion I had been in before about issues left handed people have with the world.  The question came up as to why there are so many MORE right handed people in the world.  That led me off on a search for information.

As it turns out, the world population of right handed people is between 85 and 90 percent.  Not only that, but that percentage is apparently consistent across gender, nationality, and race.  Further, it’s apparently also remained at that level for as long as it’s been tracked…approximately 500 years.

Now, it’s true that left handed people have been persecuted…and even exterminated over the course of history and, to a degree are still degraded today.  (Think of left handed sciscors.)  Even our languages have implications.  In English, the difference between “right” and “wrong” almost certainly has some origin with handedness.  In Italian, the word for a left handed person is “sinisteri” (sinister).  However, that doesn’t account for the reasons why.

A little more searching led me to find that there are actually two different genes for determining handedness and neither of them are for left handedness.  The D gene is for right handed, and the C gene is for “chance.”  Anyone with a D gene is automatically right handed.  Anyone with two C genes has a 50-50 chance of being right or left handed.

A child born to two left handed parents (who both have two C genes) would, themselves have two C genes.  But because C implies “chance” and not “left handed” the child would still have a 50-50 chance of being right handed.