Figure 2

Detecting deviations from power-law behavior. The deviations from power-law behavior can be detected by plotting the local α value vs. the scale ℓ (see Methods). The sequence with real scaling presents a constant value of α(ℓ) with small fluctuations around the linear fitting value -α_fit = 0.90 (dotted line). However, in human DNA, α(ℓ) is far from being a constant: the fluctuations around the value resulting from the linear fitting (α_fit = 0.76, dotted line) are not only very large but also following a particular pattern, indicating that this α_fit value is meaningless, and that there is no real scaling despite the good linear fitting.