Data from: A dynamical model of growth and maturation in Drosophila
Data files
Nov 29, 2023 version files 19.43 KB
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experimental_data_fed.csv
507 B
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experimental_data_stvd.csv
2.12 KB
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README.md
1.95 KB
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simulated_data_fed_ln.csv
291 B
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simulated_data_fed_sct.csv
1.54 KB
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simulated_data_stvd_ln.csv
3.71 KB
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simulated_data_stvd_sct.csv
6.39 KB
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Tyson_et_al_analysis.R
2.92 KB
Abstract
The decision to stop growing and mature into an adult is a critical point in development that determines adult body size, impacting multiple aspects of an adult’s biology. In many animals, growth-cessation is a consequence of hormone release that appears to be tied to attainment of particular body size or condition. Nevertheless, the size-sensing mechanism animals use to initiate hormone synthesis is poorly understood. Here we develop a simple mathematical model of growth cessation in Drosophila melanogaster, which is ostensibly triggered by attainment of a critical weight early in the last instar. Attainment of critical weight is correlated with synthesis of the steroid hormone ecdysone, which causes a larva to stop growing, pupate and metamorphose into the adult form. Our model suggests that, contrary to expectation, the size-sensing mechanism that initiates metamorphosis occurs before the larva reaches critical weight; that is, the critical-weight phenomenon is a downstream consequence of an earlier size-dependent developmental decision, not a decision point itself. Further, this size-sensing mechanism does not require a direct assessment of body size, but emerges from the interactions between body size, ecdysone and nutritional signaling. Because many aspects of our model are evolutionarily conserved among all animals, the model may provide a general framework for understanding how animals commit to maturing from their juvenile to adult form.
README: A dynamical model of growth and maturation in Drosophila
https://doi.org/10.5061/dryad.q573n5tq2
The data comprise experimental data used to parametrize the model, and example simulations generated by the model. The experimental data are the relationship between body mass (mg) and time to pupariation (TTP) for fed and starved third-instar Drosophila larvae (experimental_data_fed.csv and experimental_data_stvd.csv). The simulated data are the simulated relationship between body mass and TTP for fed and starved larvae without scatter (simulated_data_fed_ln.csv and simulated_data_stvd_ln.csv) and with scatter (simulated_data_fed_sct.csv and simulated_data_stvd_sct.csv).
Description of the data and file structure
All the data files contain two columns: one for body mass and a second for the time to pupariation in hours.
Code/Software
The R-script (Tyson_et_al_analysis.R) is the code used to analyze these data using loess regression and segmented regression. Script was prepared and run on R version 4.0.3.
The XPP code to generate the ecdysone and growth dynamics is provided in Tyson_et_al_XPP.txt. Script was prepared and run on XPPAUT 8.0.
The MatLab/Simulink model has two forms: one that generates the relationship between body mass and TTP without noise/scatter (single_run.m) and one that generates the same relationship but with scatter (multi_run.m). Both use the same core Simulink model (Model_simulink.slx). The scripts also generate plots of simulated versus experimental data for the relationship between body mass and TTP with and without scatter. The experimental data for these plots is contained in RealDatalmort.mat and are the same as the data used for the R-analysis. The matlab_workspace.mat file contains initial parameter values for the model. Parameter values can be specified within the single_run.m and multi_run.m scripts prior to running. Script was prepared and run on Matlab R2022b update 1.
Methods
The experimental data were collected as detailed in B. C. Stieper, M. Kupershtok, M. V. Driscoll, A. W. Shingleton, Imaginal discs regulate developmental timing in Drosophila melanogaster. Dev Biol 321, 18 26 (2008). The simulated data were generated using the deposited XPP-Auto and Simulink/Matlab scripts.