Bad driver? Then blame your genes

WASHINGTON - Bad drivers may in part have their genes to blame, suggests a new study.

According to University of Irvine scientists, people with a particular gene variant performed more than 20 percent worse on a driving test than people without it. A follow-up test a few days later yielded similar results. About 30 percent of Americans have the variant, the website Science Daily reported.

“These people make more errors from the get-go, and they forget more of what they learned after time away,” said Steven Cramer, neurology professor and senior author of the study.

This gene variant limits the availability of a protein called brain-derived neurotrophic factor during activity. BDNF keeps memory strong by supporting communication among brain cells and keeps them functioning optimally. When a person is engaged in a particular task, BDNF is secreted in the brain area connected with that activity to help the body respond.

Previous studies have shown that in people with the variant, a smaller portion of the brain is stimulated when doing a task than in those with a normal BDNF gene. People with the variant also don’t recover as well after a stroke. Given these differences, the UCI scientists wondered: Could the variant affect an activity such as driving?

“We wanted to study motor behaviour, something more complex than finger-tapping,” said Stephanie McHughen, lead author of the study. “Driving seemed like a good choice because it has a learning curve and it’s something most people know how to do.”

The driving test was taken by 29 people — 22 without the gene variant and seven with it. They were asked to drive 15 laps on a simulator that required them to learn the nuances of a track programmed to have difficult curves and turns. Researchers recorded how well they stayed on the course over time. Four days later, the test was repeated.

Results showed that people with the variant did worse on both tests than the other participants, and they remembered less the second time. “Behaviour derives from dozens and dozens of neurophysiologic events, so it’s somewhat surprising this exercise bore fruit,” Cramer said.

The results were published recently in the journal Cerebral Cortex.