Fig. 1.

Relative expression in male and female alligators of FGF9 at both early and late stages of embryogenesis and at a juvenile stage. (a) Analysis of FGF9 expression in all queried samples indicates significant variation across developmental stages. (b) Comparison of FGF9 expression before (termed early) and after (termed late) the thermally sensitive period of sex determination indicates a significant increase in FGF9 expression after sex determination among male but not female embryos. Expression increased significantly from late embryos to juvenile tissues in both males and females. (c) Comparing male and female tissue types from juvenile alligators indicates significant variation among male but not female tissues. Means were log₂-transformed for ease of visual interpretation. Lines on bars represent standard error. Numbers above bars indicate the number of biological replicates. The black diamond in figures a and b indicates the developmental stage in which sex is determined. Asterisks represent significance (*: p < 0.05; ***: p < 0.001).