Massachusetts Institute of Technology
Sign in Create Account

4 Genetic Demixing in Bacterial Colonies

Dr. Kirill Korolev, 2010–2013 Pappalardo Fellow (Soft Condensed Matter Theory & Biophysics)
The evolution of natural populations involves more than mutations followed by natural selection—the reshuffling of genes during genetic recombination, stochasticity, and spatial migrations are also important. The effects of fluctuations and spatial structure become especially pronounced when organisms spread to new territories because the number of organisms at the front of the expansion is typically small. The interplay of number fluctuations and migration causes spatial genetic demixing, i.e., spatial segregation of different genotypes. We formulated a simple phenomenological model that describes genetic demixing, and tested its predictions in bacterial colonies growing on the surface of a Petri dish. In addition, we developed a set of experimental methods to estimate important biological parameters of microbial colonies (migration rates, selective advantage, and effective population size responsible for the fluctuations). These methods could be useful for future studies of evolutionary dynamics in populations with spatial structure. More importantly, genetic demixing affects many evolutionary processes. In particular, we showed that mutualism between two species can evolve only when it is sufficiently strong and fair, i.e., both species benefit equally.

Comments (0)

It looks like no one has posted a comment yet. You can be the first!

You need to log in, in order to post comments. If you don’t have an account yet, sign up now!

May 20, 2011 13:05
All Rights Reserved (What is this?)
Additional Files

12310 times

More from The 10th Annual Pappalardo Fellowships in Physics Symposium

5 Iron-based High Tc Superconductors: How Electrons Pair by Repulsion

5 Iron-based High Tc Superconductor...

Added over 4 years ago | 00:28:28 | 9216 views

2 The Hunt for Dark Matter

2 The Hunt for Dark Matter

Added over 4 years ago | 00:33:04 | 12350 views

MIT Physics Symposium: The Pappalardo Fellowships in Physics

MIT Physics Symposium: The Pappalar...

Added over 3 years ago | 02:17:11 | 1758 views

3 Oxide interface: a Chance for New Electronics

3 Oxide interface: a Chance for New...

Added over 4 years ago | 00:23:09 | 12766 views

6 The End of Inflation

6 The End of Inflation

Added over 4 years ago | 00:22:00 | 8914 views

1 Introductory Remarks

1 Introductory Remarks

Added over 4 years ago | 00:11:47 | 3876 views