Modeling of the Dorsal Gradient across Species Reveals Interaction between Embryo Morphology and Toll Signaling Pathway during Evolution

• DOI: 10.1371/journal.pcbi.1003807
• Publication Date: 2014-08-28T17:55:05Z
• Authors: Priscilla Ambrosi; Juan Sebastian Ch...; Hannah R. Koslen; Hillel J. Chiel; Claudia Mieko Miz...
• Keywords: Morphology

Morphogenetic gradients are essential to allocate cell fates in embryos of varying sizes within and across closely related species. We previously showed that the maternal NF-κB/Dorsal (Dl) gradient has acquired different shapes Drosophila species, which result unequally scaled germ layers along dorso-ventral axis repositioning neuroectodermal borders. Here we combined experimentation mathematical modeling investigate factors might have contributed fast evolutionary changes this gradient. To end, modified a developed model employs differential equations main biochemical interactions Toll (Tl) signaling pathway, regulates Dl nuclear transport. The original simulations fit well D. melanogaster wild type, but not mutant conditions. broaden applicability probe distributions, adjusted set 19 independent parameters reproduce three quantified experimental conditions (i.e. levels lowered, size density increased or decreased). next searched for most relevant species-specific gradients. show adjusting relative morphological traits embryo diameter, density) alone is sufficient species Since components Tl pathway simulated by fast-evolving, asked would effectively these identified particular subset. A sensitivity analysis reveals existence nonlinear between two fast-evolving tested above, namely embryonic components. Our further suggests distinct observed sub-group lineages may be caused similar sequence modifications components, agreement with their phylogenetic relationships.