Most people are born right-handed, but nevertheless not many are used to doing everything with their left hand. Why is this happening? Should we call this a preference that we have since childhood, or does it have to do with neurology and appears from birth? Do lefties really show a greater tendency towards anger than other people, or are they just another myth?
New research
The distinction between left and right handed people has nothing to do with our brains or neurological development, according to a new study published in the journal eLife. Scientists have determined that in fact, your left-handedness or right-handedness took root in biology even during fetal development, but only in the form of a certain gene in the spine, and not in the brain.
Evidence suggests that it is the spinal cord, not the brain, that causes hemispheric asymmetry.
A team of researchers from Germany, the Netherlands and South Africa, led by biophysicists from the Ruhr University of Bochum, carefully monitored the expression of genes occurring in the developing spinal cord of babies growing in the womb, between the eighth and twelfth weeks of pregnancy.
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Asymmetry
It has long been assumed that the activity of genes in the brain, depending on which hemisphere shows the greatest activity, determines whether a child is born right-handed or left-handed. However, based on activity in the spinal cord, it can be assumed that there is some kind of asymmetry that has never been detected before.
This newly discovered activity occurs long before the parts of the brain responsible for movement, the motor cortex, form. Apparently, some parts of the spinal cord are responsible for transmitting electrical impulses to the arms and legs, and this asymmetry determines whether a person will write with the right hand or the left.
The reasons
In addition, the team of scientists actually managed to figure out what is causing this asymmetry. It turns out that this does not depend on regular inherited genetic mutations or traits, but on environmental factors that affect the baby while it grows in the womb.
While it is not yet clear exactly what these factors are, it is possible that they alter how enzymes work during a child's development, which in turn determines how genes are able to express themselves. Hence, this affects the asymmetry of the activity of the gene present in the spine.
So, we've learned something new! True, there is not a single word in the study about who is more prone to anger - left-handed or right-handed.
