Figure 1
From: Additive and nonadditive genetic variation in avian personality traits

Mean observed test score of the lines and crosses, for EEB (a), exploration (b) and boldness (c). Cytoplasm origin of the lines are indicated with: ○=P1 cytoplasm; •=P2 cytoplasm; =group is a mix of individuals with P1 and individuals with P2 cytoplasm. For reasons of clarity, mean values are plotted without standard errors. The lines are the regression lines based on the expected means.