Scientists in Britain and the Netherlands report they've discovered a link between handedness and a network of genes involved in establishing left-right asymmetry in developing embryos.
"The genes are involved in the biological process through which an early embryo moves on from being a round ball of cells and becomes a growing organism with an established left and right side," Oxford University doctoral student William Brandler, the study's lead author, said.
The genes may also help establish left-right differences in the brain, which in turn influences handedness, the researchers said.
Humans are the only species to show such a strong bias in handedness -- with around 90 percent of people being right-handed -- but the source of the bias has long been a mystery, they said.
In a study undertaken to identify any common gene variants that might correlate with which hand people prefer using, the most strongly associated variant with handedness was located in the gene PCSK6, which is involved in the early establishment of left and right in the growing embryo, the researchers said.
Brandler cautioned the genetic results do not fully explain the variation in handedness seen among humans.
"As with all aspects of human behavior, nature and nurture go hand-in-hand," he said. "The development of handedness derives from a mixture of genes, environment and cultural pressure to conform to right-handedness."
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