Figure 10.7 Coefficients of relatedness The coefficient of relatedness is the probability that one individual possesses the same copy of a gene as another individual through a shared relative. In this family tree, we see that the individual in the red box has a 0.5 coefficient of relatedness with its parents, siblings, and offspring. More distant relatives have lower coefficients of relatedness, as indicated by the boxes with lighter shades of red. The coefficients of relatedness are based on the assumption that none of the mates are related to the highlighted individual.