Transgenerational expression profiles of a sex related and an epigenetic control gene in the rotifer Brachionus plicatilis in relation to environmental predictability

A non-genetic transgenerational inhibitory effect on sexual reproduction has been demonstrated in Brachionus plicatilis in relation to environmental predictability. Indeed, clones of this species from more predictable environments do not respond to sex-inducing cues during several generations after leaving diapause. Notwithstanding, the molecular basis of this effect is still unknown. In this work, the expression level of genes related to the synthesis of sex hormones and to a potential epigenetic signalling mechanism were tracked along successive generations from diapausing eggs in clones of B. plicatilis populations inhabiting ponds with different level of environmental predictability. The selected genes were (1) the 17- β -dehydrogenase gene ( edh ), involved in the synthesis of 17- β- estradiol hormone in rotifers, and (2) the DNMT2 gene ( meth ), as a candidate epigenetic mechanism of control. According to expectations, results showed an increasing expression of edh across generations in clones from those the more predictable ponds. This finding provides a putative role of estradiol in the transgenerational effect. However, no differences were found in the meth gene neither across generations nor regarding the environmental predictability. Despite this, we point out alternatives for future research on the inherited gene regulation mechanism behind the transgenerational effect.