  DNA denaturation has long been a subject of intense study due to its
relationship to DNA transcription and its fundamental importance as a
nonlinear, structural transition. Many aspects of this phenomenon, however,
remain poorly understood. Existing models fit quite well with experimental
results on the fraction of unbound base pairs versus temperature. Yet, these
same models give incorrect results for other essential quantities. For example,
the predicted base pair fluctuation timescales - relevant to transcription -
are orders of magnitude different from those observed experimentally. Here, we
demonstrate that nanoscale thermal transport can serve as a sensitive probe of
the underlying microscopic mechanisms responsible for the dynamics of DNA
denaturation. Specifically, we show that the heat transport properties of DNA
are altered significantly and abruptly as it denaturates, and this alteration
encodes detailed information on the dynamics of thermal fluctuations and their
interaction along the chain. This finding allows for the unambiguous
discrimination between models of DNA denaturation. Measuring the thermal
conductance will thus shed new light on the nature of this important molecule.
