Nematode orphan genes are adopted by conserved regulatory networks and find a home in ecology

Abstract

Nematode dauer formation represents an essential survival and dispersal strategy and is one of a few ecologically relevant traits that can be studied in laboratory approaches. Under harsh environmental conditions, the nematode model organisms Caenorhabditis elegans and Pristionchus pacificus arrest their development and induce the formation of stress-resistant dauer larvae in response to dauer pheromones, representing a key example of phenotypic plasticity. Previous studies have indicated that in P. pacificus, many wild isolates show cross-preference of dauer pheromones and compete for access to a limited food source. When investigating the genetic mechanisms underlying this intraspecific competition, we recently discovered that the orphan gene dauerless (dau-1) controls dauer formation by copy number variation. Our results show that dau-1 acts in parallel to or downstream of steroid hormone signaling but upstream of the nuclear hormone receptor daf-12, suggesting that DAU-1 represents a novel inhibitor o...