Experimental evolution in Pristionchus pacificus. Experimental evolution of mouthform plasticity and transgenerational inheritance in Pristionchus pacificus

Environmental influences on traits and associated transgenerational epigenetic inheritance (TEI) have widespread implications but remain controversial and underlying mechanisms little understood. Fundamental insight could be obtained by integrating experiments that visualize plasticity in response to environmental stimuli with experimental evolution. We used long-term environmental-induction on alternative diets in the nematode Pristionchus pacificus that exhibits natural mouth-form plasticity including a predatory morph. Propagation of 110 isogenic lines for 101 generations and associated food-reversal revealed i) dietary induction of the predatory morph, ii) subsequent TEI of this predatory phenotype and iii) low-frequency canalization. We further coupled the environmental induction experiments with forward genetic screening for TEI-defective mutants. This identified a role of substrate-receptor E3 ubiquitin ligase EBAX-1.