Figure 4.

ISD results support the birth-facilitation and (preadaptation version of the) conflict resolution hypotheses. (A) Data are from the overlapping sections of the 47 gene pairs whose ages could be classified, from nonoverlapping genes in the species in which those 47 overlapping gene pairs were found, and from the 27 available preoverlapping ancestral homologs. Some numbers in the main text are for the full set of 92 overlapping gene pairs and might not match exactly. (B) While frame significantly impacts disorder content (green is consistently higher than blue), it does not drive the high ISD of overlapping genes. Even controlling for frame, novel ISD $>$ ancestral (left), supporting birth facilitation. Supporting conflict resolution, ancestral $>$ nonoverlapping either inframe (yellow) or matched frameshifted control. The preadaptation version of the constraint hypothesis is supported by the fact that nonoverlapping ISD $<$ preoverlapping (compare the two yellow bars). Means and 66% confidence intervals were calculated from the Box-Cox transformed (with λ = 0.4) means and their SE, and are shown here following back-transformation.