Anomalous diffusion in fractal globules.

Area of Science:

• Biophysics
• Computational Biology
• Genomics

Background:

• The fractal globule model is widely used to describe chromatin organization within eukaryotic nuclei.
• Understanding chromatin dynamics is crucial for comprehending nuclear processes.

Purpose of the Study:

• To investigate the thermal motion of monomers within the fractal globule state.
• To provide a theoretical and computational framework for chromatin dynamics in this model.

Main Methods:

• Development of a scaling theory for fractal globule dynamics.
• Dissipative particle dynamics (DPD) computer simulations were employed.
• Analysis of monomer motion and convergence from various initial states.

Main Results:

• Simulations demonstrated convergence, supporting the existence of a unique, metastable fractal globule state.
• Monomer motion was found to be subdiffusive, characterized by ⟨X(2)(t)⟩∼t(αF) with αF ≈ 0.4.
• The simulated dynamics align well with experimental data on chromatin motion.

Conclusions:

• The findings provide strong evidence for the fractal globule model as a valid description of chromatin packing.
• The study validates the metastable nature of the fractal globule state.
• Subdiffusive monomer motion is a key characteristic supporting the fractal globule model in eukaryotic nuclei.