PSOC Tutorials

This page contains links to computer demonstrations related to the four topics in the population dynamics tutorial. Source code for some of these demonstrations can be used to identify ways to write custom simulation scripts. The content is solely the responsibility of David Liao and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

Population dynamics

The population dynamics tutorial slide show describes basic concepts from genetic drift, fitness landscapes and quasi-species models, evolutionary game theory, and spatially-resolved models. I used graphical illustration, links to reading material, and exercises to point out

  • Basic terminology in an intuitive graphical form
  • Basic terminology in written tutorial, review article, and research article forms
  • Basic examples formatted as computer worksheets and simulation scripts
  • Examples of modern research illustrating limitations of basic terminology


Lecture slides: PowerPoint PPT (2 hrs, see also older versions)

Unit Reading Practice: Computer demonstrations and modeling skills
Genetic drift

Barbara Drossel, "Biological evolution and statistical physics," arXiv 0101409 e-print (2001) pp. 27--30

Carlo C. Maley at the Wistar Institute observes genetic diversity in Barrett's esophagus that progresses in ways that do not fit the picture of the rare and rapid fixation of a one mutant at a time in a population. Instead a variety of mutants can appear in quick succession before the initial mutant strain has enough time to dominate the population.

Wright-Fisher reproduction simulation MatLab scripts for isolated populations and metapopulations

Using sets and pseudo-random number generators in MatLab to implement probabilistic models

Fitness landscapes and quasi-species

Drossel, ibid, (2001), pp. 21--24

Brumer, Michor, Shakhnovich, "Genetic instability and the quasispecies model," J. Theor. Biol., 241: 216--222 (2006). Available online at Michor Lab web page.

1-d fitness "landscape" Excel worksheet

Calculation of error threshold in a quasi-species model with a sharp-peak fitness landscape

Evolutionary game theory

J. McKenzie Alexander, "Evolutionary game theory," Stanford Encyclopedia of Philosophy, 2002--2009 online. Sections 1 and 2.

Current uses of game theory involve complications, such as players that do not always breed true. See for instance the non-technical discussion by Casey Jones, "Game theory shows evolution follows most successful member," Ars Technica 2010 January 19 (Available online).

2x2 evolutionary game with replicator dynamics Excel worksheet

Working with difference and differential equations using MatLab

Spatially-resolved models

Alexander, ibid (2002--2009), Figures 4, 5, and 6.

Nowak and May, "Evolutionary games and spatial chaos," Nature 359: 826--829 (1992).

Benjamin C. Kirkup and Margaret A. Riley, "Antibiotic-mediated antagonism leads to a bacterial game of rock-paper-scissors in vivo," Nature 428, 412--414 (2004).

Benjamin Kerr, Margaret A. Riley, Marcus W. Feldman, and Brendan J. M. Bohannan, "Local dispersal promotes biodiversity in a real-life game of rock-paper-scissors," Nature 418, 171--174 (2002).

Modern spatially-resolved models sometimes explicitly describe diffusion of chemicals that influence cell growth so some cellular interactions occur indirectly. Irregular lattices can be used instead of rectangular lattices. J. L. Gevertz and S. Torquato, "Modeling the effects of vasculature evolution on early brain tumor growth," J. Theor. Biol. 243: 517 (2006). Available online from Sal Torquato's publications page.

C. Athena Aktipis, Arizona State University, has prepared a guide to agent-based modeling including links to free graphical-user-interface-based software for modeling agents in spatially-resolved environments.

See erratum re: Nowak and May description in dissertation and tutorial.

Spatially-resolved simulation MatLab scripts

Using arrays to represent local processes in spatially-distributed systems in MatLab: Using the convolution theorem for efficient computation.

Entropy


Lecture slides: PowerPoint PPT (1.5 hrs)

Unit Reading Practice and skills
Entropy
Information and diversity

"Efficient representation," Chapter 4 from W. Bialek, Biophysics: Searching for Principles. http://www.princeton.edu/~wbialek/PHY562.html (2010).

Statistical mechanics and thermodynamics

Charles Kittel and Herbert Kroemer, Thermal Physics 2nd ed. W. H. Freeman (1980) Amazon.com entry

Derivation of free energy by maximizing entropy in a closed system composed of two parts sharing a conserved total energy

Derivation of relationship between free energy and maximum work

Software

Unzipper
Microsoft PowerPoint 2003