Plasticity and genetic basis of cichlid gill arch anatomy reveal novel roles for Hedgehog signaling

Teleost gill arches are exquisitely evolved to maximize foraging efficiency, and include structures for the capture, filtering, processing of prey. While both plasticity a genetic basis arch traits have been noted, relative contributions genetics environment in shaping these remains poorly understood. East African cichlids particularly useful this line study due their highly diverse plastic feeding apparatus. Here we explore gene-by-environmental effects on cichlid GRs by rearing pure bred species F3 hybrids different environments. We find that anatomical differences between dependent environment. The architecture is also largely distinct did, however, note few genomic “hotspots” where multiple map common region. One these, GR number across arches, maps ptch1 locus, key component Hedgehog (Hh) pathway has previously implicated oral jaw shape plasticity. Since Hh signalling not development, explored functional roles pathway. Using small molecule inhibitor cichlids, as well zebrafish transgenic systems, demonstrate levels negatively regulate number, necessary sufficient maintain trait. In all data underscore critical importance determining relationship genotype phenotype, provide molecular inroad better understand origins variation important foraging-related