  Charge transfer is considered in systems composed of a donor, an acceptor and
bridge sites of (AT) nucleotide pairs. For a bridge consisting of 180 (AT)
pairs, three cases are dealt with: a uniform case, when all the nucleotides in
each strand are identical; an ordered case, when nucleotides in each DNA strand
are arranged in an orderly fashion; a chaotic case, when (AT) and (TA) pairs
are arranged randomly. It is shown that in all the cases a charge transfer from
a donor to an acceptor can take place. All other factors being equal, the
transfer is the most efficient in the uniform case, the ordered and chaotic
cases are less and the least efficient, accordingly. The results obtained are
in agreement with experimental data on long-range charge transfer in DNA.
