Electronic Transport in DNA

We study the electronic properties of DNA by way of a tight-binding model applied to four particular DNA sequences. The charge transfer properties are presented in terms of localisation lengths, crudely speaking the length over which electrons travel. Various types of disorder, including random potentials, are employed to account for different real environments. We have performed calculations on poly(dG)-poly(dC), telomeric-DNA, random-ATGC DNA and lambda-DNA. We find that random and lambda-DNA have localisation lengths allowing for electron motion among a few dozen base pairs only. A novel enhancement of localisation lengths is observed at particular energies for an increasing binary backbone disorder. We comment on the possible biological relevance of sequence dependent charge transfer in DNA.