In high school biology you probably learned that every one of our body’s cells contains the same genome, or pattern of DNA—but it turns out that this is not true of the brain. Researchers at the Salk Institute for Biological Studies recently found that the DNA sequence in human neurons can vary not only from that of the rest of the body but even from one brain cell to the next.
The reason is “jumping genes,” DNA elements that can copy and reinsert themselves in different places within the genome. These mutations increase the total amount of DNA in each neuron. Geneticist Fred H. Gage and his team at Salk looked at a type of mobile element called LINE-1. Although LINE-1s are present in all cells of the body, they appeared to be active only in developing brain cells, the researchers found.
The jumping genes generate neuronal diversity, which might help the brain adapt, Gage speculates. “Many of the things that we are going to be presented with throughout our lives are unanticipated,” he says. The higher the neuronal variety in the brain, the higher the chances that it contains some cells that are capable of rising to these cognitive challenges.
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Note: This story was originally printed with the title "Jumping DNA"
