Fig. 4From: Variation in the ontogeny of sex steroid levels between latitudinal populations of the medakaOntogenetic changes in the ratio of testosterone to estradiol-17β levels in laboratory-reared individuals from two latitudinal populations. The ratio of T to E2 per unit tissue was calculated for each individual and plotted against SL. A cubic spline curve was fitted separately for each sex, using the gam function in the mgcv package in R ver. 2.13.0Back to article page