Fig. 6: Model and model testing.

a, Model; see text for details. b, Top, quantitative Western blot analysis of yolk content (EO95 mAb; H3, loading control) in the indicated species and RNAi conditions. Bottom, bar graph representation of RNAi-control-normalized EO95 signal. Error bars, s.d. of two to four technical replicates (dots) of n = 1 biological replicate. c, Yolk gland cross-sectional area quantifications in sagittal sections of the indicated species and RNAi treatments. White oulines, yolk glands; red frames, zooms. d, Bar graph representation of c. Error bars, s.d. of the mean of n = 4 individuals (dots), each representing the mean of five technical replicates. e, Correlation between yolk gland cross-sectional area and regenerative abilities in the indicated egg-laying species. Species ordering by relative yolk content quantified as in c,d; colours: head-regeneration abilities (green, robust/group A; orange, restricted/group B; red, poor/group C). Error bars, s.d. of the mean of n = 4 individuals (dots), each representing the mean of five technical replicates. f, Statistical analysis of the data in e, replotted as log₁₀ of mean yolk content/individual in group A versus B and C species. Red line, distribution mean. Significance assessment via linear mixed model; the indicated P value implies statistical significance. g, Calibration of the G78 mAb for interspecies comparisons. Western blot of recombinant His-tagged ß-CATENIN-1 fragments of the indicated species and probed with anti-penta-His Ab (top) or G78 mAb (bottom); ratio, species-specific correction factor. Molecular weight marker as indicated. h, Correlation between Wnt pathway activity, regenerative abilities (colour coding as in e) and reproduction mode (bottom) across the indicated species. Species ordering by ß-CATENIN-1 concentrations in tail lysates, as per corrected G78 mAB signal. Error bars, s.d. of the mean of n = 3 biological replicates (dots), each representing the mean of four technical replicates. i, Statistical analysis of the data in h, replotted as log₁₀ of the mean ß-CATENIN-1 tail tip concentration in fissiparous versus egg-laying strains/species (left) or robust versus restricted or poor regeneration groups (A versus B and C). Red line, distribution mean. Significance assessment as in f; the indicated P values imply lack of significance.