On the Left Hand, There Are No Easy Answers

Are you left or right-handed? Well according to an article by Perri Klass on the NYTimes, approximately 90% of people are right-handed leaving the remaining 10% to left-handed people. Even though hand dominance is related to brain asymmetry, it runs in the family. Geneticist, Clyde Francks with a group of Oxford researchers discovered a gene, LRRTM1 which is associated with the development of left-handedness. Even though there are genetic connections between preference, Dr. Geschwind says that “It’s not a single gene that leads to it. There’s a strong environmental component, too. It’s a very tricky problem.” Left-handers are seen to have less asymmetric brains which many believe to be linked to various conditions. I think this article is very interesting as I'm a left-hander myself. I do believe that it has something to do with genetics since my dad, brother, and I are all left-handed in the family. We are rare and it's interesting to see which presidents are also left-handed. Us, left-handers greatness lies in the way they integrate motor control, strength, and different kinds of skills and intelligence. 

Scientists Identify Genetic Components of Left-Handedness

Researchers from the University of Oxford identified four DNA regions that related to handiness after they analyzed genomes of approximately 400,000 UK individuals  It was found that three of those regions influenced genes that code for the proteins that have to do with brain development.  The proteins have a big part in making microtubules which help with the construction of cells and form part of the cytoskeleton.  The genes that help form the cytoskeleton are also what causes right and left differences in the development of animals.  For example; whether a snail's shell coils to the left or to the right.  

The researchers also studied brain scans of approximately 9,000 individuals from the study.  They also found that with people who were left-handed, the parts of the brain that work with language worked together more orderly.  This begs the question: Could people who are left-handed be better at carrying out verbal tasks?  When the researchers combined the results from the brain imaging and the genetic results, they found that some of the genes related to handiness connected to cytoskeletal differences that join the language areas of the brain together.  Because of these scans, for the first time, researchers were able to actually see the handedness differences in the brain.  

They also found that the genes related to left-handedness had a very small increased risk of schizophrenia and a reduced risk of Parkinson's disease.  Of course, this would need to be researchers further but these findings could lead to many other questions for genetic studies with these diseases.  It is interesting that now we can actually see the differences of right-handed people and left-handed people in the brain scans and with studying genes as well.  I think it would be good to look into these genes and how they are related to diseases more because with further research we may be able to tell who is more or less likely going to develop certain diseases, like Parkinson's or schizophrenia. 

https://www.medicalnewstoday.com/articles/326278.php
https://academic.oup.com/brain/advance-article/doi/10.1093/brain/awz257/5556832

Why Left Handedness?

Why is left handedness so puzzling? It only accounts for 12% of the world's population. Yet, so many famous people have been left handed as well as five out of our last seven presidents to Einstein to the first man on the moon. What is it, genetically speaking, about left handedness, that explains this phenomenon?

To begin, the left handed origins have been observed in Neanderthals. Scientists studied the grooves in their teeth from them scratches they made while carving their food up and found that one in every ten Neanderthal scratched their teeth towards the left side. This can give us some insight as to how long the genes have influenced left handedness. However, scientists still do not understand what genes and how many are in play to cause left handedness.

We do have a clue as to how it affects left handed people, however. Left handedness and intelligence seem to go hand in hand. Left handers disproportionately make up the small amount of people with a genius iq. For example, twenty percent of Mensa members (society where one must have a high iq) are left handed. For only about ten percent of left handed people making up the population, this is an interesting fact. There are some drawbacks to being left handed, however. 40% of schizophrenic people are left handed. Scientists believe this happens to left handed people who have equal access to both sides of the brain. This can cause complex messages to the brain that can result in misconnections in neural networks and thus causing the symptoms of schizophrenia. The science is not in on this yet, however.






One thing is for sure. Left handedness should be studied more and understood. Many household names are left handed people that changed the world with their way of thinking. Science could have a breakthrough if they can understand how schizophrenia develops by studying the biological markers in left handed people. In any case, the left handed people are an important anomaly to understand, and essential in shaping our music, politics, and technology.


http://www.mirror.co.uk/news/technology-science/science/lefty-righty-here-astonishing-statistics-4757193

http://www.bbc.com/future/story/20160930-the-mystery-of-why-left-handers-are-so-much-rarer

http://www.anythinglefthanded.co.uk/being-lh/lh-info/advantages.html

http://healthland.time.com/2013/11/01/the-connection-between-left-handedness-and-schizophrenia/