Contaminants and impoSEX: transcriptomics of contaminant-induced sex change.

Reproduction is the goal of living organisms, and environmental conditions that influence sexual development are therefore critical to understanding adaptation in natural populations. It is not surprising that so much attention has been devoted to the impacts of the physical and chemical environment on this process (Vandenberg et al.2012). Chemicals of concern include a variety of endocrine disruptors (EDs) including oestrogen and oestrogen mimics that directly lead to malformation of the gonad. On the molecular side, the impact that EDs have on genes directly involved in the feminization or masculinization of the gonad such as Cyp 19A (or aromatase), foxl2,Sox9, Dmrt1 and NrOb1, has received considerable attention due to their direct involvement in the regulation of oestrogen and testosterone. In this issue of Molecular Ecology, Pascoal et al. (2013) examine the impact of a known endocrine disruptor (tributyltin or TBT) on the transcriptome of the dog whelk, Nucella lapillus (Fig. 1),in relation to the formation of imposex individuals (masculinized females). They conclude that TBT mimics the endogenous ligand of the nuclear retinoid X receptor (RXR) and/or peroxisome profilerator-activated receptor (PPAR) disrupting pathways.