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Genes may determine whether we are right-handed or left-handed, according to a new study.

A new study found correlations 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," first author William Brandler, a PhD student in the MRC Functional Genomics Unit at Oxford University, said in a news release.

Researchers say that the genes that determine handedness may also help establish left-right differences in the brain.

Researchers said that humans are the only species to show such a strong preference in handedness, and the fact that 90 percent of people in the world are right-handed remains a mystery.

Researchers were interested in understanding which genes might have an influence on handedness to understand the causes and evolution of handedness.

Researchers found that the most significant variant with handedness is located in the gene PCSK6, which is involved in the early establishment of left and right in the growing embryo.

Previous studies of PCSK6 and similar genes revealed that disrupting the gene causes 'left-right asymmetry' defects, such as abnormal positioning of organs in the body. For instance, mice with a faulty PCSK6 gene might have a heart and stomach on the right and a liver on the left side of their bodies.

Other variants in genes known to cause left-right defects when disrupted in mice were significantly associated with relative hand skill.

While the researchers have identified a role for genes involved in establishing left from right in embryo development, researchers stress that these study results do not completely explain the variation in handedness seen among humans.

"As with all aspects of human behavior, nature and nurture go hand-in-hand. The development of handedness derives from a mixture of genes, environment, and cultural pressure to conform to right-handedness," Brandler explained.

The findings are published in the journal PLOS Genetics.