DNA

Left‐handedness occurs in about 8% of the human population. It runs in families and an adoption study suggests a genetic rather than an environmental origin. Since prehistoric times, left-handed individuals have been ubiquitous in human populations, exhibiting geographical frequency variations. Evolutionary explanations have been proposed for the persistence of the handedness polymorphism. Left-handedness could be favored by negative frequency-dependent selection. Data have suggested that left-handedness, as the rare hand preference, could represent an important strategic advantage in fighting interactions. However, the fact that left-handedness occurs at a low frequency indicates that some evolutionary costs could be associated with left-handedness. Overall, the evolutionary dynamics of this polymorphism are not fully understood. So, it might come as a surprise to some that the first genetic markers associated with imparting the left handed gene have now been discovered.