The logic of transgenerational inheritance in a nematode worm.

Epigenetic inheritance of environmentally induced phenotypes across generations has been observed in multiple taxa. However, the dynamics of non-genetic inheritance as a consequence of environmental variability remains poorly understood. Here, we take advantage of the transgenerational epigenetic inheritance (TEI) of an environmentally induced cannibalistic trait in the nematode Pristionchus pacificus. Using alternative environmental induction and superinduction experiments, we illustrate how environmental variability regimes influence TEI and uncover the dosage-dependent nature of the trigger molecule-vitamin B12-on the onset of TEI. Our study provides a unique example of the dynamics of TEI of an ecologically relevant trait as a consequence of environmental variation.