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Ever wondered why you are right-handed or left handed?
Contrary to popular belief, it has nothing to do with our brains or neurological development.
It has long been presumed by scientists that the reason for our right and left-handedness is a result of an activity in the right and left hemispheres of our brain during fetal development. But a new study carried out by a team of scientists from Ruhr-Universitat Bochum, Germany concluded that the spinal cord, not the brain, is responsible for asymmetries.
“Our data suggest a spinal, not a cortical, beginning of hemispheric asymmetries,” the researchers concluded.
In the study, the team used fetal ultrasound to monitor the earliest signs of gene activity in marking asymmetry and preference. They discovered that a preference for the right hand or left hand can be observed as early as eight weeks. The fetus was also found to suck either their right or left thumb from the thirteenth week of pregnancy.
Interestingly, the motor complex, a part of the brain responsible for arm and hand movements, has not yet made its connection at eight weeks. This means that precursors of handedness have been established even before the brain tells the spinal cord what to choose.
In addition, the researchers also found that symmetry is not affected by inherited genetic mutations or traits.
Environmental factors possibly alter how enzymes operate around the developing fetus and influence how their genes are able to express themselves. As a result, it influences the asymmetry of gene activity in the spine.
