Figure 4
From: Statistical distributions of optimal global alignment scores of random protein sequences
Distribution of scores from global alignments of the RUS sequence set of 100aa long. The alignments were carried out with the BLOSUM50 matrix and an affine gap penalty of -10 and -2. This sequence set include 300 sequences whose E-value to each other is greater than 10. The distribution of the scores was fitted with three distribution curves indicated by the solid line. (A) The scores were fitted with the gamma distribution. The fitted parameters are: γ = 53.0052, λ = 0.406777, μ = -176.022, χ2 value is 13.7903 with d.f. = 10; (B) The scores were fitted with the normal distribution. The fitted parameters are: σ = 17.898, μ = -45.717; d.f. = 11, χ2 = 308.925; (C) The scores were fitted with the Gumbel distribution. The fitted parameters are: β = 13.95498, μ = -53.771; d.f. = 11, χ2 = 4659.8.