Sampling rare events: Statistics of local sequence alignments
Abstract
A method to calculate probability distributions in regions where the events are very unlikely (e.g., p~10^{40}) is presented. The basic idea is to map the underlying model on a physical system. The system is simulated at a low temperature, such that preferably configurations with originally low probabilities are generated. Since the distribution of such a physical system is known, the original unbiased distribution can be obtained. As an application, local alignment of protein sequences is studied. The deviation of the distribution p(S) of optimum scores from the extremevalue distribution is quantified. This deviation decreases with growing sequence length.
 Publication:

Physical Review E
 Pub Date:
 May 2002
 DOI:
 10.1103/PhysRevE.65.056102
 arXiv:
 arXiv:condmat/0108201
 Bibcode:
 2002PhRvE..65e6102H
 Keywords:

 05.10.a;
 87.10.+e;
 87.15.v;
 Computational methods in statistical physics and nonlinear dynamics;
 General theory and mathematical aspects;
 Biomolecules: structure and physical properties;
 Condensed Matter  Disordered Systems and Neural Networks;
 Quantitative Biology
 EPrint:
 5 pages, 4 figures, revtex