  Unusually high bending flexibility has been recently reported for DNA on
short length scales. We use atomic force microscopy (AFM) in solution to obtain
a direct estimate of DNA bending statistics for scales down to one helical
turn. It appears that DNA behaves as a Gaussian chain and is well described by
the worm-like chain model at length scales beyond 3 helical turns (10.5nm).
Below this threshold, the AFM data exhibit growing noise because of
experimental limitations. This noise may hide small deviations from the
Gaussian behavior, but they can hardly be significant.
