Short tandem repeats, or STRS, are tiny stretches of repeated DNA that might be more significant than scientists originally thought.

It was once believed that the length of the repeat (only) can change how nearby genes switch on and off, especially in the brain. Researchers recently found, however, that the pattern of the repeat also plays a role.

In genetic data from more than 3,000 people, researchers found that some STRs fluctuate in sequence and tend to sit near Alu elements, or “jumping genes,” which can move to different positions within the genome.

They were typically thought of as genetically functionless, but their movement impacts the genome variation and causes genetic diseases and more.

These variations were linked to changes in the gene activity involved in brain development, memory and cell communication.

The study also found that people of African descent had the greatest variety in these repeat patterns. Altogether, the findings suggest that these tiny DNA stutters may play a quiet but meaningful role in shaping how our brains function and how we differ from one another.

The paper was published in Genome biology.

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