A study published in the Journal of Neuroscience found that a version of a gene coding for a receptor for the brain chemical dopamine was 66% more common among people who lived to be 90 or older than among a group of younger people who were otherwise similar. The variant leads to a weaker response to the neurotransmitter, lowering the activity of the dopamine system that is responsible for generating feelings of pleasure, desire and reward, as well as for regulating movement.
via Could A Dopamine Gene Be the Answer to a Longer Life? | TIME.com.