Most analyses of gene expression focus on changes in the mean: significant increases or decreases across all samples analysed. We find changes in variability equally interesting, since they represent newly gained or relaxed controls in reaction to a stressor, and therefore open avenues of evolution and adaptation. We use zebrafish maternal RNA for our analyses. Maternal RNA is deposited by the mother into the egg, and thus represents a significant inherited information source. It is also largely devoid of intrinsic noise, since mature oocytes are transcriptionally and translationally silent, and mRNAs are protected from degradation. Also, we can easily obtain a large number of biological replicates from one clutch. This is an ideal setting to investigate variability in a context of heritability.
