Tissue-specific profiles of gene emergence. The accumulative number of emerging genes (y-axis) in the deuterostomia-mammalia evolutionary window (x-axis) is represented for different tissue-specific genetic programs. We termed these representations gene emergence plots. At the chordate-vertebrate transition the rate of gene emergence (ger) was estimated for the different genetic programs. (a) Using mouse phenotypic annotations we calculated ger values between chordata and vertebrata for each main phenotype structure in the database. Structures are highlighted from blue to yellow, according to decreasing values of ger. Neural crest derivative structures are present within the highest ger values (red box). (b) Plots of representative structures of each class of ger value: class I = ger > 3; class II = 3 > ger > 1.5; and class III: ger < 1.5.