When I was a baby, my mother would perform the practice of giving me toys to see which hand I would choose to pick them up with. When I disregarded my right hand in favour of using my left, she was astonished. Only a few days later it was all but confirmed- I was a leftie, and therefore part of a highly rare group of people that contributed less than 10% to the world's population.
Come my adolescence, nothing has changed. I eat with my left hand, write with my left hand, do pretty much everything that requires a hand to be used with my left hand. This has begged the question- what causes left-handedness, and why does it exist?
Before the 21st century, things weren't easy for left-handers. Much to my own surprise, left-handedness had a highly negative stigma attached to it, and many lefties suffered greatly for not being right-handed. Even now, the word 'right' is synonymous with 'correct', or 'good', and other positive adjectives, while 'left' is...not. The word itself is derived from the Anglo-Saxon word lyft, meaning weak. The right hand of Jesus is the favoured hand for blessings and providence, whilst his left hand is used for divine punishment and judgement of the wicked. Those who fall from God's favour are sent 'to the left' in Christianity, which is synonymous with hell. Black magic is commonly referred to as the 'left-hand path', which is associated with Satanism.
While the world has grown more accepting of lefties come the 21st century, their troubles haven't ended yet. In a world where ninety per cent of the population is right-handed, most products are engineered for right-handed use. Left-handers often injure and sometimes even kill themselves using appliances meant for rightie use with their left hand, such as power saws, cars, and firearms. And I find it impossible to cut things with scissors!
What makes this bias intrinsically unfair is that left-handers are born that way. Recently, scientists have isolated a gene called PSCK6, which may control handedness in humans. They found this especially interesting, as it is also a gene responsible for left-right asymmetry in the body- like how some of our organs are placed more to the left than the right and vice-versa. Mutating this gene, as well as the other genes that are responsible for developing left-right asymmetry is what may cause left-handedness. To what degree these genes are mutated is what draws the line between the left hand's or the right hand's dominance. However, incorrectly mutating the genes may cause our organs to be flipped. (For example, our heart may be placed in the right side of our ribcage.) This condition is incredibly dangerous and has been termed as situs inversus.
Moreover, further research has shown that handedness is also determined by that of one's parents in very consistent ratios. If the father was a leftie and the mother a rightie, the child would have a 17% chance of being a leftie. Two righties would have a left-handed child only 10% of the time. A left-handed mother would have a 22% chance of bearing a left-handed child with a rightie partner but would have a 25% chance with a leftie father.
This may also explain why there are so few left-handers in the world- only about one in every group of ten. It's been that way for almost 50,000 years according to archaeological evidence. However, what it doesn't explain is why this mutation has not yet been eradicated completely. In a world where the bias is against lefties, Darwinism indicates that the mutation should have been wiped out ages ago. After all, it provides little advantage to our daily lives to be lefties...right?
Wrong! At least, not completely right! Left-handers actually have a significant advantage in certain sports such as basketball and baseball, where the ball is thrown with the left hand. This gives it a completely different angle of approach, a different spin, and different direction. Righties facing a left-handed opponent would, therefore, have a significant disadvantage. How would a rightie batter, for example, face a pitched ball that is different in every way from what he usually practices with? This would also be true in almost any activity involving an opponent.
The above example can be grouped into a branch of Darwinism known as negative frequency-dependent selection, where the rarer a trait, the more valuable it is.
Now, you may be crying out, "But! If lefties had such an advantage, then the mutation would have spread until left-handedness wasn't an advantage! If right-handedness was a disadvantage, then it would have been eradicated by Darwinism until both were at a 50-50 ratio!"
Remember what I said about society being biased against lefties? As aforementioned, lefties often face difficulty by using tools mostly designed with a right-handed clientele in mind. They would thus be less successful in this world and be whittled down. So, by maintaining a balance of the advantages and disadvantages that are granted to a left-handed person, we may see that the 10% number has been decided by these two selective pressures, and probably will be maintained in the years to come.
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For more math and science-focused articles that will be uploaded frequently, please follow my blog on Blogger.com! It's easy- just create your own account on Blogger, click on 'Reading list', 'edit', then 'add'. Thank you so much for reading!
Before the 21st century, things weren't easy for left-handers. Much to my own surprise, left-handedness had a highly negative stigma attached to it, and many lefties suffered greatly for not being right-handed. Even now, the word 'right' is synonymous with 'correct', or 'good', and other positive adjectives, while 'left' is...not. The word itself is derived from the Anglo-Saxon word lyft, meaning weak. The right hand of Jesus is the favoured hand for blessings and providence, whilst his left hand is used for divine punishment and judgement of the wicked. Those who fall from God's favour are sent 'to the left' in Christianity, which is synonymous with hell. Black magic is commonly referred to as the 'left-hand path', which is associated with Satanism.
While the world has grown more accepting of lefties come the 21st century, their troubles haven't ended yet. In a world where ninety per cent of the population is right-handed, most products are engineered for right-handed use. Left-handers often injure and sometimes even kill themselves using appliances meant for rightie use with their left hand, such as power saws, cars, and firearms. And I find it impossible to cut things with scissors!
What makes this bias intrinsically unfair is that left-handers are born that way. Recently, scientists have isolated a gene called PSCK6, which may control handedness in humans. They found this especially interesting, as it is also a gene responsible for left-right asymmetry in the body- like how some of our organs are placed more to the left than the right and vice-versa. Mutating this gene, as well as the other genes that are responsible for developing left-right asymmetry is what may cause left-handedness. To what degree these genes are mutated is what draws the line between the left hand's or the right hand's dominance. However, incorrectly mutating the genes may cause our organs to be flipped. (For example, our heart may be placed in the right side of our ribcage.) This condition is incredibly dangerous and has been termed as situs inversus.
Moreover, further research has shown that handedness is also determined by that of one's parents in very consistent ratios. If the father was a leftie and the mother a rightie, the child would have a 17% chance of being a leftie. Two righties would have a left-handed child only 10% of the time. A left-handed mother would have a 22% chance of bearing a left-handed child with a rightie partner but would have a 25% chance with a leftie father.
This may also explain why there are so few left-handers in the world- only about one in every group of ten. It's been that way for almost 50,000 years according to archaeological evidence. However, what it doesn't explain is why this mutation has not yet been eradicated completely. In a world where the bias is against lefties, Darwinism indicates that the mutation should have been wiped out ages ago. After all, it provides little advantage to our daily lives to be lefties...right?
Wrong! At least, not completely right! Left-handers actually have a significant advantage in certain sports such as basketball and baseball, where the ball is thrown with the left hand. This gives it a completely different angle of approach, a different spin, and different direction. Righties facing a left-handed opponent would, therefore, have a significant disadvantage. How would a rightie batter, for example, face a pitched ball that is different in every way from what he usually practices with? This would also be true in almost any activity involving an opponent.
The above example can be grouped into a branch of Darwinism known as negative frequency-dependent selection, where the rarer a trait, the more valuable it is.
Now, you may be crying out, "But! If lefties had such an advantage, then the mutation would have spread until left-handedness wasn't an advantage! If right-handedness was a disadvantage, then it would have been eradicated by Darwinism until both were at a 50-50 ratio!"
Remember what I said about society being biased against lefties? As aforementioned, lefties often face difficulty by using tools mostly designed with a right-handed clientele in mind. They would thus be less successful in this world and be whittled down. So, by maintaining a balance of the advantages and disadvantages that are granted to a left-handed person, we may see that the 10% number has been decided by these two selective pressures, and probably will be maintained in the years to come.
----------------------------------------------
For more math and science-focused articles that will be uploaded frequently, please follow my blog on Blogger.com! It's easy- just create your own account on Blogger, click on 'Reading list', 'edit', then 'add'. Thank you so much for reading!
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