  Previous theoretical studies have shown that measuring the transverse current
across DNA strands while they translocate through a nanopore or channel may
provide a statistically distinguishable signature of the DNA bases, and may
thus allow for rapid DNA sequencing. However, fluctuations of the environment,
such as ionic and DNA motion, introduce important scattering processes that may
affect the viability of this approach to sequencing. To understand this issue,
we have analyzed a simple model that captures the role of this complex
environment in electronic dephasing and its ability to remove charge carriers
from current-carrying states. We find that these effects do not strongly
influence the current distributions due to the off-resonant nature of tunneling
through the nucleotides - a result we expect to be a common feature of
transport in molecular junctions. In particular, only large scattering
strengths, as compared to the energetic gap between the molecular states and
the Fermi level, significantly alter the form of the current distributions.
Since this gap itself is quite large, the current distributions remain
protected from this type of noise, further supporting the possibility of using
transverse electronic transport measurements for DNA sequencing.
