An abstract model to determine the relative physical constraint of three linked loci in wt and mutant strains.

<p>A) The forward mathematical approach allows determining features of a subpopulation of relative positions between 3 loci in space. The inverse computational approach consists in modeling the relative positions or survival zones of loci whose positions are spatially linked. The underlying polymer fiber imposes constraints on the positions each locus can adapt. Iterative calculation defines the survival zones of each locus (or node) which can predict biological relevant features. B-C) Survival Zones (Z) of <i>HML</i>, <i>MAT</i> and <i>HMR</i>. The initial position of the 3 loci is set based on the estimated conformation for Chr3 (B). Iterations were run using <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004306#pcbi.1004306.e050" target="_blank">Eq 25</a> (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004306#sec002" target="_blank">Methods</a>) and the statistically most significant zones are represented for wt, <i>asf1</i> mutants and strains in which the recombination enhancer element was deleted (C).