The fraction of configurations with exactly and at least N anchors. (A) Plot of the fraction of configurations with exactly N anchors,, as N varies. An anchor is a run of at least K correct bases (shown for K = 15, 20, and 25). We assume the read length is L = 1000 and the error rate per base is ρ = 15%(and that there are exactly M = 150 error positions). The solid markers are computed by finding exact coefficients cM,N,K(L) in the generating functions. The curve is a normal distribution approximating the exact values (illustrating Theorem A3), where parameters μ and σ2are computed by Theorem A2. (B) The solid markers are a plot of, the fraction of configurations with at least N anchors, as N varies. The parameters are the same as for (A). The curve is the survival function of the normal distribution in (A).