Left- or right-brain? Genes may tell the story

According to HHMI investigator Christopher A. Walsh, postdoctoral fellow Tao Sun, and their colleagues at Beth Israel Deaconess Medical Center and Harvard Medical School, their discovery that a gene called LM04 is expressed differently on the two sides of the brain may help understand how one side of the brain is dominant in most people.

Perhaps more important, this normal asymmetry of the brain is disrupted “in a host of human neurological diseases, including dyslexia, schizophrenia and other disorders,” Walsh said. “So this may offer us entry into how such problems relate to the development of the human brain.”

They didn’t believe in the claim made by some researchers that there are specific genes for each side of the brain, Walsh said. “One thing we did know is that there are higher levels of gene expression in the front of the brain compared to the back.”

Years of brain research have shown that distinct functional “maps” exist in the cerebral cortex. Animals come equipped with places to receive sensory input from the different parts of the body, explained Walsh.

This led to the hypothesis that differences in gene expression might be responsible for human right brain/left brain dominance.