Data from: Sex-specific changes in gene expression in response to estrogen pollution around the onset of sex differentiation in grayling (Salmonidae)

The synthetic 17α-ethinylestradiol (EE2) is a common estrogenic pollutant
that has been suspected to affect the demography of river-dwelling
salmonids. One possibility is that exposure to EE2 tips the balance during
initial steps of sex differentiation, so that male genotypes show
female-specific gene expression and gonad formation. Here we study EE2
effects on gene expression around the onset of sex differentiation in a
population of European grayling (Thymallus thymallus) that suffers from
sex ratio distortions. We exposed singly-raised embryos to one dose of 1
ng/L EE2, studied gene expression 10 days before hatching, at the day of
hatching, and around the end of the yolk-sac stage, and related it to
genetic sex (sdY genotype). We found that exposure to EE2 affects
expression of a large number of genes, especially around hatching. These
effects were strongly sex-dependent. We then raised fish for several
months after hatching and found no evidence of sex reversal in the
EE2-exposed fish. We conclude that ecologically relevant (i.e. low) levels
of EE2 pollution do not cause sex reversal by simply tipping the balance
at early stages of sex differentiation, but that they interfere with
sex-specific gene expression.