Hyper-sound as a means for generating inter-strand defects in a duplex of the DNA

TL;DR

This paper models DNA as a disordered harmonic lattice to study how hyper-sound can induce inter-strand defects, potentially leading to bubble formation in the DNA duplex.

Contribution

It introduces a theoretical model linking hyper-sound excitation to inter-strand defect formation in DNA using Lifshits theory and lattice dynamics.

Findings

Spectra of elastic eigen-modes show peaks at high frequencies.

External hyper-sound can induce parametric resonance.

Resonance may lead to localized modes and bubble formation.

Abstract

The formation of bubble defects of the double stranded DNA is treated according to the Lifshits theory of disordered chains. A molecule of the DNA is modelled on a harmonic lattice with nearest neighbour interaction, elastic constants being randomly distributed. The helicoidal symmetry is accommodated through a chiral field at sites of the lattice. The number of sites varies from 100 to 300, corresponding to DNA segmnets of persistence length. We find the spectra of elastic eigen-modes that mimic inter-strand excitations of the duplex. The frequency distribution shows peaks and valleys at the high-frequency end of the spectra, in accord with the general theory. External excitations may lead to a parametric resonance that can generate localized modes of the lattice. In real life pumping hyper-sound may generate a resonance similar to that studied in this paper, and thus result in excitation of inter-strand modes and possible formation of bubbles, in the duplex of the DNA.