Systems Biology
Systems biology is an integrative, holistic approach to understanding biological organisms by studying the complex interactions among components — genes, proteins, metabolites, and cells — rather than examining them in isolation. It combines high-throughput experimental data (genomics, proteomics, metabolomics) with mathematical modelling, network analysis, and computational simulation to predict emergent behaviours of living systems. Applications include understanding drug resistance, modelling disease progression, and designing synthetic gene circuits.
Systems Biology Modelling Approaches
| Modelling Approach | Method | Scale | Strength | Example |
|---|---|---|---|---|
| Ordinary Differential Equations (ODE) | Continuous deterministic | Molecular / cellular | Captures dynamic kinetics | Lac operon switch model |
| Boolean networks | Discrete logic (ON/OFF) | Gene regulatory networks | Simple, scalable | Cell cycle phase transitions |
| Flux Balance Analysis (FBA) | Linear optimisation | Metabolic networks | No kinetic parameters needed | E. coli metabolic model |
| Agent-based models | Stochastic simulation | Multi-cellular / tissue | Models spatial heterogeneity | Tumour growth simulation |
| Bayesian networks | Probabilistic graphical model | Gene networks | Learns from noisy data | Inferring gene regulatory networks |
Interactive Tools
COPASI (Biochemical Simulation)
Simulate and analyse biochemical networks using ODEs and stochastic methods
Open ToolSystems Biology Markup Language (SBML)
Standard format for storing and exchanging computational models of biological systems
Open ToolKEGG PATHWAY
Map molecular interactions and metabolic networks for pathway-level systems analysis
Open Tool
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Related Terms
Bioinformatics
Bioinformatics is an interdisciplinary field that develops and applies computational methods, algorithms, and software tools to analyse and interpret large-scale biological data, particularly sequences of DNA, RNA, and proteins. It integrates biology, computer science, mathematics, and statistics to address problems such as genome assembly, sequence alignment, phylogenetic analysis, and structural prediction. The field is indispensable for modern genomics, drug discovery, and personalised medicine.
Metabolomics
Metabolomics is the systematic, large-scale study of small-molecule metabolites (< ~1500 Da) — such as amino acids, lipids, sugars, and organic acids — present in a biological sample, reflecting the downstream functional output of genomic, transcriptomic, and proteomic changes. Nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) coupled to chromatography are the primary analytical platforms, capable of detecting hundreds to thousands of metabolites simultaneously. Metabolomics is applied in biomarker discovery, drug toxicology, nutritional science, and understanding metabolic diseases such as type 2 diabetes.
Synthetic Biology
Synthetic biology is an engineering-driven discipline that applies principles of design and standardisation to build new biological parts, devices, and systems, or to redesign existing natural biological systems for useful purposes. It integrates molecular biology, genetic engineering, bioinformatics, and systems biology to create standardised genetic "parts" (BioBricks), gene circuits that behave like logic gates, and entirely synthetic genomes. Applications include engineering microbes to produce biofuels, pharmaceuticals, and biomaterials, as well as creating biosensors and living diagnostics.
From Greek "systema" (organised whole) + Latin "biologia" (study of life). While a holistic view of organisms has deep roots, modern systems biology emerged in the early 2000s, catalysed by the human genome project and championed by researchers such as Leroy Hood.