Excluded Volume Effects in Gene Stretching

TL;DR

This paper explores how excluded volume effects influence the stretching behavior of DNA, revealing non-linear extension-force relationships and differences between two and three dimensions, supported by experimental data fitting.

Contribution

It introduces a model incorporating excluded volume effects that accurately fits experimental DNA stretching data and compares behaviors across dimensions.

Findings

Extension h scales as F^{rac{1- u}{ u}} at small forces

Model fits experimental data of NA well

Excluded volume effects are more pronounced in two dimensions

Abstract

We investigate the effects excluded volume on the stretching of a single DNA in solution. We find that for small force F, the extension h is not linear in F but proportion to F^{\chi}, with \chi=(1-\nu)/\nu, where \nu is the well-known universal correlation length exponent. A freely joint chain model with the segment length chosen to reproduce the small extension behavior gives excellent fit to the experimental data of \lambda-Phage DNA over the whole experimental range. We show that excluded volume effects are stronger in two dimensions and also derive results in two dimensions which are different from the three dimensional results. This suggests experiments to be performed in these lower dimensions.