title: Evolution of early development in dipterans: reverse-engineering the gap gene network in the moth midge Clogmia albipunctata (Psychodidae).
abstract: Understanding the developmental and evolutionary dynamics of regulatory networks is essential if we are to explain the non-random distribution of phenotypes among the diversity of organismic forms. Here, we present a comparative analysis of one of the best understood developmental gene regulatory networks today: the gap gene network involved in early patterning of insect embryos. We use gene circuit models, which are fitted to quantitative spatio-temporal gene expression data for the four trunk gap genes hunchback (hb), Krüppel (Kr), giant (gt), and knirps (kni)/knirps-like (knl) in the moth midge Clogmia albipunctata, and compare them to equivalent reverse-engineered circuits from our reference species, the vinegar fly Drosophila melanogaster. In contrast to the single network structure we find for D. melanogaster, our models predict four alternative networks for C. albipunctata. These networks share a core structure, which includes the central regulatory feedback between hb and knl. Other interactions are only partially determined, as they differ between our four network structures. Nevertheless, our models make testable predictions and enable us to gain specific insights into gap gene regulation in C. albipunctata. They suggest a less central role for Kr in C. albipunctata than in D. melanogaster, and show that the mechanisms causing an anterior shift of gap domains over time are largely conserved between the two species, although shift dynamics differ. The set of C. albipunctata gene circuit models presented here will be used as the starting point for data-constrained in silico evolutionary simulations to study patterning transitions in the early development of dipteran species.
authors.affiliation: EMBL/CRG Research Unit in Systems Biology, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain. Electronic address: anton.crombach@crg.eu.
authors.forename: Anton
authors.initials: A
authors.lastname: Crombach
authors.affiliation: Laboratory for Development and Evolution, University Museum of Zoology and Department of Zoology, Downing Street, Cambridge CB2 3EJ, UK.
authors.forename: Mónica A
authors.initials: MA
authors.lastname: García-Solache
authors.affiliation: EMBL/CRG Research Unit in Systems Biology, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Johannes
authors.initials: J
authors.lastname: Jaeger
mesh_terms: D000465:Algorithms; D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D003198:Computer Simulation; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics; D008957:Models, Genetic; D009036:Moths / Q000196:embryology / Q000235:genetics*; D013045:Species Specificity; D013997:Time Factors
chemical_list: D019476:Insect Proteins
keywords: Clogmia albipunctata; Drosophila melanogaster; Evolutionary developmental biology; Gap gene network; Network evolution; Reverse-engineering