Genetics of human handedness and laterality

Handedness is the most evident lateralized trait in humans. A weak (~25 %) genetic component has been consistently reported for hand preference across independent studies. Genomic technologies have made rapid progress in increasing throughput and resolution of genetic mapping but their success is largely dependent on the availability of large sample sizes. Hand preference in humans is easily determined and available for tens of thousands of individuals for which genomic data are also available. Yet, strong genetic candidates for hand preference have not been proposed yet. Genetics analyses using quantitative measures of handedness have demonstrated that genes involved in establishing left/right structural laterality play a role in controlling behavioral laterality. Therefore it is crucial how handedness is measured and it is clear that other genetic determinants remain to be discovered. The combination of detailed phenotypes with high throughput technologies promises to advance, in the near future, our understanding of handedness genetics and, in turn, the relevant biology. These discoveries will contribute to addressing one of the long-standing questions in laterality research: what makes some people left-handed?