While genes associated with schizophrenia and autism based on positive associations in the GAD (Figure 2) reveal no significant signal of positive selection on the human branch relative to apes or other primates, catarrhines in general show higher average dN/dS when compared to other mammals, with the exception of the cetaceans (Tursiops truncatus and Orcinus orca). This evidence concerns the gene GAD1 and autism.