No, I am not left-handed. Actually, no one in my family is a “lefty” (except one of my cousins). So I decided to do this blog for her. When I think about left-handedness, I believe, personally, that it is in one’s genes. That was my hypothesis going into this; one is born left-handed and it gets passed down.
During my research, I fell upon an article from the Scientific American, where Clare Porac, who is actually a professor of psychology here at Penn State (WE ARE!) pointed out that left-handedness begins either in genes or by biological causes. One theory she found was that natural selection created lots of people with language and speech control on the LEFT side of their brain. The LEFT side of the brain is known to control the RIGHT hand and written language. They say there are two alleles, the D gene and the C gene. The D gene is the right-handed gene and the C gene is the left-handed gene. If someone has the C gene, they have a fifty-percent chance of being left-handed, which is minimal in this case.
In a resent article from PLOS Genetics, they did a genome-wide association study meta-analysis and discovered that certain genes are related to left/right body asymmetry. They used mice to test this hypothesis, very similar to humans. So since this seems to be a genetic thing, why is left-handedness still occurring? That is because this left-handedness occurs as a result of a lot more genes than just dominant and recessive ones like the old days. Wonderopolis.org says, “since scientists have noticed that left-handedness tends to run in families, it’s assumed that left-handedness has a genetic component to it. In other words, left-handers are born that way.”
Another study took a little different of a toll on this idea. This study, done in 1972 by British psychologist Marian Annett, was also known as the Right Shift Theory. She concluded that left-handers do not inherit the gene for left-handedness, instead they get the absence of neurological bias toward the dominant left hemisphere. She also said random events during one’s childhood, such as a school telling a kid to use their right hand to write and not left, may actually lead to a little bit of influence on the actual handedness. This means that genetics make more of a difference for right handers because they have more dominant handedness genes in general.
Maybe in the future, some more testing can be done. Maybe…is it possible for someone to change their handedness on their own? We could get one group of right-handed people and try to train them to write with their left-hand and see if it works. You never know unless you try, right? So in conclusion, they are many reasons scientists believe one is left-handed. From my research, I have learned that the majority of these people believe it comes from genes.