R E C E N T D I V E R G E N C E D E S P I T E M I G R AT I O N Table 2. Estimated mutation rates based on mutation rate scalars. Locus One102 One105 One108 One109 One115 Geometric mean Scalar estimate Average 0.9092 0.1298 4.406 0.7292 3.0129 SD (0.0097) (0.0028) (0.0812) (0.0277) (0.1403) Calibrated scalar 7.0046 1 33.9448 5.6181 23.2116 Mutation rates per generation 0.0007 0.0001 0.00339 0.00056 0.00232 0.00079 per year 0.00014 0.00002 0.00068 0.00011 0.00046 0.00016 (m) ranged between 0.00009875 and 0.002706 and mean proba- bility estimates of migration rate ranged between 0.003377 and 0.006379 (Fig. 6). High point probability estimates of the average date of all migration events ranged between 42 and 120 years ago (Table 5). Mean probability estimates of the average date of all migration events ranged between 177 and 305 years ago (Table 5). High point probability estimates of the effective num- ber of migrants (parameters θ × m/2) ranged between 0.16 and 9.0 (Table 6). Mean probability estimates of the posterior prob- ability of the effective number of migrants ranged between 8.9 and 18.4 (Table 6). High point estimates of NE ranged between 740–1655 for beach, 528–988 for outlet, and 5047–5588 for an- cestral (Fig. 7). Mean probability estimates of NE ranged between Table 3. Mutation rate estimates based on length of repeat method. We include length of repeat and corresponding mutation rates for each marker. Locus One102 One105 One108 One109 One115 Geometric means No. of repeats 15.22 7.55 18.44 15.63 25.69 Mutation rates per generation 0.00325 0.000085 0.00884 0.00374 0.0497 0.003399 per year 0.00065 0.000017 0.001768 0.000748 0.00994 0.00068 Table 4. Comparison of the high point, average values, 95% cred- ibility interval, and 90% highest posterior density (HPD) of the posterior distribution of divergence onset dates in years before sample collection for all three runs of the IM program. Run 1 Run 2 Run 3 Mean SD High point 111 47 123 93.7 (40.9) Average 389 503 396 429.3 (63.9) 95% credibility interval 66–1725 54–4358 73–3022 90% HPD 35–1206 22–2528 28–1560 1386–1709 for beach, 961–1394 for outlet, and 5561–5967 for ancestral (Fig. 7). Our results from our MIGRATE analysis were very similar to our results with IM in all the common parameters, NE and migration rate (Table 7). Figure 5. Posterior probability distributions for time since diver- gence in years. All three runs of the IM program are illustrated; run 1 is black dashed, run 2 is black, run 3 is gray. The inset is an enlargement of years 1–1000. Figure 6. Posterior probability of migration rates between pop- ulations. The composite ﬁgure of all three runs of the migration rate posterior probability distributions shows the beach to outlet migration as a gray line on a black ﬁeld. The line is the average probability for the three runs, and the black ﬁeld is the standard er- ror ﬁeld. The outlet to beach average probability is the thick white line, and the standard error space around the line is depicted by the thin white lines. EVOLUTION JUNE 2010 1 7 7 9