Table 1. Island method estimates for λ and K.

c	Rc	λc	Kc
20	508 087 143	0.2790 0.0000 (0.00%)	0.058
21	382 046 389	0.2771 0.0000 (0.01%)	0.056
22	288 047 946	0.2754 0.0000 (0.01%)	0.053
23	217 666 586	0.2739 0.0000 (0.01%)	0.051
24	164 854 001	0.2726 0.0000 (0.01%)	0.050
25	125 090 432	0.2716 0.0000 (0.01%)	0.048
26	95 080 777	0.2707 0.0000 (0.01%)	0.047
27	72 367 615	0.2700 0.0000 (0.01%)	0.046
28	55 135 823	0.2694 0.0000 (0.01%)	0.045
29	42 040 928	0.2689 0.0000 (0.02%)	0.044
30	32 087 753	0.2685 0.0000 (0.02%)	0.044
31	24 502 349	0.2681 0.0001 (0.02%)	0.043
32	18 721 366	0.2678 0.0001 (0.02%)	0.043
33	14 312 497	0.2676 0.0001 (0.03%)	0.042
34	10 945 852	0.2674 0.0001 (0.03%)	0.042
35	8 372 081	0.2672 0.0001 (0.03%)	0.042
36	6 407 611	0.2671 0.0001 (0.04%)	0.042
37	4 904 102	0.2670 0.0001 (0.05%)	0.041
38	3 755 281	0.2671 0.0001 (0.05%)	0.042
39	2 874 422	0.2670 0.0002 (0.06%)	0.041
40	2 201 167	0.2671 0.0002 (0.07%)	0.042
41	1 684 893	0.2670 0.0002 (0.08%)	0.041
42	1 289 490	0.2669 0.0002 (0.09%)	0.041
43	986 932	0.2667 0.0003 (0.10%)	0.041
44	756 060	0.2668 0.0003 (0.12%)	0.041
45	579 087	0.2668 0.0004 (0.13%)	0.041
46	443 934	0.2671 0.0004 (0.15%)	0.042
47	339 913	0.2671 0.0005 (0.17%)	0.042
48	260 519	0.2675 0.0005 (0.20%)	0.042
49	199 117	0.2671 0.0006 (0.22%)	0.042
50	152 595	0.2674 0.0007 (0.26%)	0.042
51	116 705	0.2671 0.0008 (0.29%)	0.042
52	89 323	0.2671 0.0009 (0.34%)	0.042
53	68 605	0.2680 0.0010 (0.38%)	0.044
54	52 570	0.2686 0.0012 (0.44%)	0.045
55	40 242	0.2690 0.0013 (0.50%)	0.046
56	30 746	0.2690 0.0015 (0.57%)	0.046
57	23 481	0.2688 0.0018 (0.65%)	0.046
58	17 888	0.2678 0.0020 (0.75%)	0.043
59	13 662	0.2673 0.0023 (0.86%)	0.042
60	10 427	0.2664 0.0026 (0.98%)	0.039

A total of 92 441 pairs of length 7000 random sequences were generated using a set of standard amino acid frequencies (26). Island scores were generated for each pair using an extension of the Smith–Waterman algorithm (5), modified for affine gap scores (28). Substitutions were scored using the BLOSUM-62 matrix (27), and gaps of length k were assessed the score –(11 + k). Scores were recorded only for islands anchored within the central 5000 × 5000 square of each pairwise comparison. Maximum-likelihood estimates for λ and K were obtained using equations 4–6.