Extended Data Fig. 2: Schematic representation of the two alternative foreground schemes used to identify positively selected genes in flatfishes using the aBSREL model in HyPhy.

a, Stem flatfishes, which aimed to detect genes responsible for the initial break of symmetry in the single branch leading to all extant flatfish species. b, Crown flatfishes, which aimed to detect genes responsible for further adaptations experienced later in the flatfish radiation.