Quantitative system drift compensates for altered maternal inputs to the gap gene network of the scuttle fly Megaselia abdita

• Published in: eLife Vol. 4
• Main Authors: Wotton, Karl R, Jiménez-Guri, Eva, Crombach, Anton, Janssens, Hilde, Alcaine-Colet, Anna, Lemke, Steffen, Schmidt-Ott, Urs, Jaeger, Johannes
• Format: Journal Article
• Language: English
• Published: England eLife Sciences Publications Ltd 05-01-2015; eLife Sciences Publications, Ltd
• Subjects: Abdomen; Animals; Biology; Blastoderm; Body Patterning - genetics; Chironomidae; Culicidae; data quantification; Databases, Genetic; Developmental Biology and Stem Cells; developmental system drift; Diptera - embryology; Diptera - genetics; Drift; Drosophila melanogaster; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Drosophilidae; Embryo, Nonmammalian - metabolism; Evolution; Evolution, Molecular; evolutionary developmental biology; Female; gap gene network; Gene expression; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Genes, Insect; Genomics and Evolutionary Biology; Megaselia abdita; Mosquitoes; Phylogenetics; Psychodidae; RNA Interference; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-mediated interference; Segmentation; stem cells; RNA interference; developmental system drift; evolutionary biology; developmental biology; evolutionary developmental biology (evo-devo); gap gene network; Megaselia abdita; data quantification; genomics; D. melanogaster
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.04785

The segmentation gene network in insects can produce equivalent phenotypic outputs despite differences in upstream regulatory inputs between species. We investigate the mechanistic basis of this phenomenon through a systems-level analysis of the gap gene network in the scuttle fly Megaselia abdita (Phoridae). It combines quantification of gene expression at high spatio-temporal resolution with systematic knock-downs by RNA interference (RNAi). Initiation and dynamics of gap gene expression differ markedly between M. abdita and Drosophila melanogaster, while the output of the system converges to equivalent patterns at the end of the blastoderm stage. Although the qualitative structure of the gap gene network is conserved, there are differences in the strength of regulatory interactions between species. We term such network rewiring 'quantitative system drift'. It provides a mechanistic explanation for the developmental hourglass model in the dipteran lineage. Quantitative system drift is likely to be a widespread mechanism for developmental evolution.