Packaging and accessing DNA molecules

The DNA molecules in our cells are several centimeters long and need to fit into the cell nucleus. To do this, DNA segments are wrapped around protein cylinders to form nucleosomes. To access the DNA, nucleosomes must be shifted to alternating positions in a process known as nucleosome sliding, in which the nucleosomes move along the DNA in a corkscrew fashion. We discovered that this process can be mapped onto a generalized version of a fundamental model of low-dimensional nonlinear physics, the Frenkel-Kontorova model. In this model, we discovered surprising phenomena, including an acceleration of diffusion for longer DNA segments.