A study published on April 2nd in Nature Communications suggests that genetic variations causing protein alterations and genes related to microtubule proteins may be associated with the formation of human left-handedness. These findings could potentially enhance our understanding of the genetic basis of handedness.
Only about 10% of people are left-handed, a phenomenon that arises when the right hemisphere of the brain predominates in controlling this hand (opposite for right-handed individuals). The asymmetry in brain dominance for the preferred hand appears early in life, indicating a possible genetic influence. Previous population studies have identified some common genetic variations associated with left-handedness. Among these variations are some that involve genes encoding microtubule proteins, which are part of the cellular skeleton supporting cell structure. However, it remains unclear how these genes influence handedness.
To further investigate the genetic basis of handedness, Clyde Francks and colleagues from the Max Planck Institute for Psycholinguistics in the Netherlands conducted a genome-wide screening using data from over 350,000 individuals in the UK Biobank to identify rare genetic variations associated with left-handedness. The analysis included 38,043 left-handed individuals and 313,271 right-handed individuals.
The study found that at the population level, the heritability of left-handedness due to rare coding variations was less than 1%. They also discovered that a gene encoding a microtubule protein called TUBB4B had a 2.7 times higher likelihood of rare coding variations in the left-handed population compared to the right-handed population.
The authors also investigated the extent to which genes previously associated with schizophrenia, Parkinson's disease, Alzheimer's disease, and autism are related to handedness. They suggest that two genes previously linked to autism (DSCAM and FOXP1) may also be associated with left-handedness, although causality has not been determined.
For more information, refer to the related paper: https://doi.org/10.1038/s41467-024-46277-w
