How are reptiles capable of generating such a diversity of bright colors? And how is it possible that within a single population of the same species, different individuals exhibit strikingly different coloration patterns? In a new paper published in the journal PNAS an international team of scientists, led by researchers from CIBIO/InBIO (University of Porto) and Uppsala University, reveal two genes implicated in yellow to red pigmentation in reptiles, and demonstrate that these pigmentation genes also affect behavior and other traits.