Organisms are responsive to environmental variation. However, little is known on how genetic regulation of development is linked to environmental changes. Phenotypic plasticity, the property of a single genotype to produce distinct phenotypes dependent on the environmental conditions, provides a unique opportunity to study organismal-environmental interactions. The nematode Pristionchus pacificus
is a new model for studying phenotypic plasticity. P. pacificus
forms two distinct mouth-forms and is accessible to an unbiased studying of phenotypic plasticity.