How much of your cerebellum’s size is in your DNA?

The cerebellum—located at the back of your brain—controls movement, balance, and coordination. Scientists already knew its overall size is mostly genetic, but what about specific regions?

In a study led by Lachlan Strike, researchers have used MRI scans from two large twin groups of twins—one with 798 young adults (average age 22) and another with 396 adolescents (average age 11)—to measure 28 different regions of the cerebellum. Here’s what they found:

• Genes play a big role, but not equally everywhere: 47 to 91 per cent of size differences are genetic, but influence varies by region.
• Consistent results: Repeat scans confirm that non-genetic differences likely come from life experiences like diet, exercise, or injuries.
• Left and right sides are linked: Paired regions are strongly connected, mainly due to shared genes.

Why this is important:

• Explains why some people may be more prone to movement or coordination disorders.
• Paves the way for genome-wide studies on brain development.
• Shows how genes set the blueprint, while environment fine-tunes the details.

Your cerebellum’s size and shape are largely written in your DNA, but not all parts are equally influenced by genes. This study shows that specific regions vary in how much they’re controlled by genetics