title: The impact of gene expression variation on the robustness and evolvability of a developmental gene regulatory network.
abstract: Regulatory interactions buffer development against genetic and environmental perturbations, but adaptation requires phenotypes to change. We investigated the relationship between robustness and evolvability within the gene regulatory network underlying development of the larval skeleton in the sea urchin Strongylocentrotus purpuratus. We find extensive variation in gene expression in this network throughout development in a natural population, some of which has a heritable genetic basis. Switch-like regulatory interactions predominate during early development, buffer expression variation, and may promote the accumulation of cryptic genetic variation affecting early stages. Regulatory interactions during later development are typically more sensitive (linear), allowing variation in expression to affect downstream target genes. Variation in skeletal morphology is associated primarily with expression variation of a few, primarily structural, genes at terminal positions within the network. These results indicate that the position and properties of gene interactions within a network can have important evolutionary consequences independent of their immediate regulatory role.
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Garfield
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Runcie
authors.forename: Courtney C
authors.initials: CC
authors.lastname: Babbitt
authors.forename: Ralph
authors.initials: R
authors.lastname: Haygood
authors.forename: William J
authors.initials: WJ
authors.lastname: Nielsen
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Wray
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001842:Bone and Bones / Q000033:anatomy & histology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D007814:Larva / Q000033:anatomy & histology / Q000235:genetics; D047270:Strongylocentrotus purpuratus / Q000235:genetics* / Q000254:growth & development