Figure 2. Internal fluctuation of 
DNA confined in a 80 nm
130 nm channel.
(A) The measured rms fluctuation 
versus mean extension 
for the internal segments of the DNA agrees very well with de Genne's theory with no fitting parameters (red curve, Eq.4). (B) A linear 
profile confirms the 
power law of 
of the de Gennes' theory. Note, however, that here we have maximum 
m. As shown in a subsequent figure (Fig. 4) and in the text, for longer polymer with a maximum 
m, the data deviates significantly from de Gennes' theory and even the 0.5 power law is lost.