Figure 2: Examination of maternal effects using reciprocal crosses.

Here “upregulated” means more highly expressed in that group. (a) Expected pattern of DE genes for purely maternal effects. The offspring of H × H and H × W crosses shared a mother. The offspring of the W × H and W × W crosses also shared a mother (See Fig. 1). If there were maternal effects, we would expect, after normalizing counts across all DE genes, that the offspring of H × W crosses would be more similar to the H × H offspring and that the offspring of the W × H fish would be more similar to the W × W fish. (b) We observed that most of the genes have an additive effect, in that expression values for H × W and W × H offspring are intermediate. Bars represent 95% confidence intervals for all DE genes (n=723). This result suggests that very few genes are DE due to maternal effects.