dsDNa fit to WLc model Hooke’slaw 0.01 0.4 0.8 Extension(X/L) After Bustamante et al., Current Opinion in Structural Biology, 2001FJC dsDNA 100 10 1 0.1 0.01 Hooke’s law fit to WLC model Force (pN) 0 0.2 0.4 0.6 0.8 1.0 1.2 Extension (x/L) After Bustamante et al., Current Opinion in Structural Biology, 2001