Abstract
The omnigenic model suggests the existence of core networks of genes for quantitative traits, which are influenced by modifiers that may encompass most, if not all expressed genes in the genome. We have studied pupation site choice behaviour in Drosophila to test this model. Based on a GWA analysis of the Drosophila Genetic Reference Panel (DGRP) stocks, we identify candidate genes and show for disrupted versions of the genes that most are indeed involved in the phenotype. These candidate genes also allowed us to identify a core network and we experimentally confirm the involvement of other members of this core network in the trait. Intriguingly, when randomly choosing 20 non-network genes we also find an involvement in the trait for most of them. Comparison of phenotypic effect sizes suggest that the core network genes have on average stronger effects. Our data thus confirm the predictions of an omnigenic genetic architecture.