In recent years, more and more human behaviours that once were thought to be learned are found to have a genetic component.

Hereditary family signature of facial expression (The link may not work for you)

The way a person expresses anger, sadness, concentration,... in her face runs in families even in congenitally blind family members. The (first time) investigation of congenitally blind family members rules out the old interpretation that the facial expressions concomitant to emotions are picked up visually.

Wolfgang