Of the four genetic regions they identified, three of these were associated with proteins involved in brain development and structure. These proteins were related to microtubules, which are part of the scaffolding inside cells, called the cytoskeleton, which guides the construction and functioning of the cells in the body. Researchers found that these genetic effects were associated with differences in brain structure in white matter tracts, which contain the cytoskeleton of the brain that joins language-related regions.
"We discovered that, in left-handed participants, the language areas of the left and right sides of the brain communicate with each other in a more coordinated way. This raises the intriguing possibility for future research that left-handers might have an advantage when it comes to performing verbal tasks, but it must be remembered that these differences were only seen as averages over very large numbers of people and not all left-handers will be similar."
For the first time, researchers can establish that these handedness-associated cytoskeletal differences are actually visible in the brain. We know from other animals, such as snails and frogs, that these effects are caused by very early genetically-guided events, so this raises the tantalizing possibility that the hallmarks of the future development of handedness start appearing in the brain in the womb.
The researchers also found correlations between the genetic regions involved in left-handedness and a very slightly lower chance of having Parkinson's disease, but a very slightly higher chance of having schizophrenia. However, the researchers stressed that these links only correspond to a very small difference in the actual number of people with these diseases and are correlational, so they do not show cause-and-effect. Studying the genetic links could help to improve understanding of how these serious medical conditions develop.
Hence, researchers have demonstrated that left-handedness is a consequence of the developmental biology of the brain, in part driven by the complex interplay of many genes.
Category(s):Child Development
Source material from Science Daily
