Results Directory UMM :Data Elmu:jurnal:J-a:Journal of Experimental Marine Biology and Ecology:Vol246.Issue1.MAr2000:

72 H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 HW equilibrium conditions were tested with exact probability tests, implemented by the GENEPOP software v. 1.1 Raymond and Rousset, 1995, which applies the Markov chain method proposed by Guo and Thompson 1992. Interarchipelago differences in MNA or H were investigated by means of two obs analyses of variance, using the software package STATISTICA v. 5.0 Statsoft, 1995. Genetic population differentiation can be expressed by means of hierarchical F- statistics. When a hierarchical arrangement of populations is assumed, in this case populations P being placed within islands I, archipelagos A and total distribution area T, the variance of the observed genetic differentiation among the populations var can be split up into its variance components. A series of F-statistics can be ST obtained e.g., F , F , F and F , of which the terms in the following equation PI IA PT AT 1 2 F 5 1 2 F ? 1 2 F ? 1 2 F PT PI IA AT represent respectively: total differentiation, differentiation among populations within islands, differentiation among islands within archipelagos, and differentiation among archipelagos. These F-values are not additive. Hence, F reflects only the additional IA variance among islands beyond that which exists among populations, and F reflects AT only additional variance among archipelagos beyond that which exists among islands Wolf and Campbell, 1995. F-values and corresponding variance components were calculated with the WRIGHT78 option in BIOSYS Swofford and Selander, 1989. Allele frequency heterogeneities among the four archipelagos, were evaluated with Fisher exact tests applied to R 3C contingency tables as implemented by the GENEPOP v. 1.1 software Raymond and Rousset, 1995. The differentiation among islands was further analyzed by means of correspondence analysis, executed with the NTSYS v. 1.80 software Rohlf, 1993. Gene flow Nm among archipelagos was estimated using private allele frequencies Slatkin, 1985; Slatkin and Barton, 1989. Pairwise Nm values were plotted against pairwise geographical distances, enabling us to calculate the correlation coefficient and corresponding regression equation. A significance level of 5 was used throughout. The sequential Bonferroni technique was employed to correct for false assignments of significance by chance alone multiple test problems Rice, 1989.

3. Results

Allele frequencies, H , H , and the results of the HW-tests are given in Table 2. obs exp Six deviations from HW equilibrium were detected, yet none of these remained significant after Bonferroni correction. Eight alleles were unique to the CV archipelago GPI-G, MPI-F, PGD-B, PGD-F, MDH-B, MDH-C, MDH-E and HBDH-F and two alleles were unique to the AZ MDH-A, HBDH-A. Private allele frequencies used for estimating Nm among archipelagos are given in Table 4 below. MNA differed among the four archipelagos, with CV appearing genetically more diverse overall MNA 54.2, than the other archipelagos overall MNA53.2 Fig. 1. H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 73 Table 2 Allele frequencies, observed H and expected H heterozygosity levels and exact probabilities P-ext obs exp for deviation of Hardy–Weinberg equilibria population abbreviations see Table 1 Locus AZ1 AZ2 AZ3 AZ4 AZ5 AZ6 AZ7 AZ8 AZ9 AZ10 GPI N 38 37 37 38 38 40 37 34 39 36 A 0.026 0.014 0.014 0.013 0.026 0.013 0.027 0.029 0.000 0.014 B 0.303 0.297 0.284 0.434 0.237 0.325 0.297 0.309 0.244 0.236 C 0.039 0.000 0.000 0.013 0.079 0.000 0.000 0.015 0.077 0.069 D 0.593 0.689 0.688 0.514 0.632 0.612 0.622 0.544 0.653 0.653 E 0.000 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.000 0.000 F 0.039 0.000 0.014 0.026 0.013 0.050 0.054 0.103 0.026 0.028 G 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.711 0.297 0.405 0.474 0.474 0.475 0.432 0.588 0.333 0.556 obs H 0.554 0.436 0.444 0.547 0.538 0.517 0.522 0.597 0.507 0.512 exp P-ext 0.065 0.044 0.729 0.711 0.061 0.743 0.501 0.910 0.001 0.341 MPI N 39 40 40 32 38 40 40 39 37 40 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.051 0.138 0.125 0.094 0.053 0.075 0.087 0.115 0.108 0.075 C 0.949 0.862 0.875 0.906 0.947 0.912 0.913 0.885 0.892 0.912 D 0.000 0.000 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.013 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.103 0.225 0.200 0.188 0.105 0.150 0.175 0.231 0.216 0.175 obs H 0.097 0.237 0.219 0.170 0.100 0.162 0.160 0.204 0.193 0.162 exp P-ext 1.000 0.548 0.473 1.000 1.000 0.083 1.000 1.000 1.000 1.000 PGD N 38 38 39 37 37 38 34 35 34 37 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 C 1.000 0.974 1.000 0.946 0.986 0.974 0.971 0.977 0.956 1.000 D 0.000 0.026 0.000 0.027 0.014 0.000 0.000 0.000 0.029 0.000 E 0.000 0.000 0.000 0.027 0.000 0.026 0.029 0.043 0.015 0.000 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H – 0.053 – 0.054 0.027 0.053 0.059 0.086 0.088 – obs H – 0.051 – 0.102 0.027 0.051 0.057 0.082 0.085 – exp P-ext – 1.000 – 0.028 – 1.000 1.000 1.000 1.000 – MDH N 40 37 39 37 40 39 36 37 37 40 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.014 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 C 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 D 1.000 1.000 1.000 1.000 1.000 1.000 1.000 0.986 1.000 1.000 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H – – – – – – – 0.027 – – obs H – – – – – – – 0.027 – – exp P-ext – – – – – – – – – – HBDH N 36 40 40 39 37 38 36 35 40 40 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.000 0.038 0.025 0.013 0.027 0.013 0.042 0.014 0.025 0.000 C 0.986 0.899 0.899 0.884 0.865 0.961 0.902 0.986 0.962 0.949 D 0.014 0.000 0.013 0.026 0.027 0.000 0.014 0.000 0.000 0.013 E 0.000 0.063 0.063 0.077 0.081 0.026 0.042 0.000 0.013 0.038 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.028 0.200 0.200 0.231 0.270 0.079 0.194 0.029 0.075 0.100 obs H 0.027 0.185 0.185 0.211 0.244 0.077 0.181 0.028 0.073 0.096 exp P-ext – 1.000 1.000 1.000 1.000 1.000 1.000 – 1.000 1.000 74 H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 Table 2. Continued Locus AZ11 AZ12 AZ13 AZ14 AZ15 AZ16 AZ17 AZ18 AZ19 AZ20 GPI N 36 36 35 39 36 39 28 39 40 37 A 0.014 0.014 0.014 0.013 0.000 0.013 0.000 0.000 0.000 0.027 B 0.236 0.333 0.400 0.321 0.375 0.204 0.393 0.372 0.250 0.284 C 0.014 0.042 0.014 0.013 0.028 0.026 0.000 0.026 0.013 0.027 D 0.708 0.541 0.543 0.601 0.583 0.731 0.589 0.538 0.674 0.648 E 0.014 0.028 0.000 0.026 0.000 0.000 0.000 0.013 0.000 0.000 F 0.014 0.042 0.029 0.026 0.014 0.026 0.018 0.051 0.063 0.014 G 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.500 0.528 0.514 0.436 0.500 0.487 0.393 0.538 0.375 0.486 obs H 0.442 0.591 0.544 0.533 0.518 0.422 0.498 0.568 0.478 0.497 exp P-ext 0.664 0.028 0.430 0.537 0.736 0.926 0.234 0.769 0.280 0.592 MPI N 39 38 37 39 40 33 38 40 39 38 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.115 0.132 0.108 0.128 0.063 0.106 0.132 0.063 0.141 0.158 C 0.885 0.868 0.892 0.872 0.937 0.894 0.868 0.932 0.846 0.842 D 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.013 0.000 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.231 0.211 0.162 0.256 0.075 0.212 0.211 0.125 0.231 0.263 obs H 0.204 0.229 0.193 0.224 0.117 0.190 0.229 0.117 0.264 0.266 exp P-ext 1.000 0.493 0.344 1.000 0.124 1.000 0.493 1.000 0.084 1.000 PGD N 34 37 33 37 40 39 38 39 36 36 A 0.000 0.014 0.000 0.014 0.000 0.000 0.000 0.000 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 C 0.985 0.959 0.955 0.958 0.937 0.987 0.961 0.962 0.988 0.988 D 0.000 0.000 0.000 0.014 0.000 0.013 0.000 0.038 0.014 0.000 E 0.015 0.027 0.045 0.014 0.063 0.000 0.039 0.000 0.028 0.042 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.029 0.081 0.091 0.081 0.125 0.026 0.079 0.077 0.083 0.083 obs H 0.029 0.079 0.087 0.079 0.117 0.025 0.076 0.074 0.081 0.080 exp P-ext – 1.000 1.000 1.000 1.000 – 1.000 1.000 1.000 1.000 MDH N 40 39 33 39 40 39 38 39 40 38 A 0.000 0.013 0.000 0.013 0.000 0.000 0.013 0.000 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 C 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 D 1.000 0.987 1.000 0.987 1.000 1.000 0.987 1.000 1.000 1.000 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H – 0.026 – 0.026 – – 0.026 – – – obs H – 0.025 – 0.025 – – 0.026 – – – exp P-ext – 1.000 – 1.000 – – 1.000 – – – HBDH N 40 39 35 40 37 40 35 38 39 38 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.013 0.000 B 0.000 0.026 0.014 0.050 0.014 0.025 0.014 0.079 0.038 0.026 C 0.912 0.846 0.972 0.900 0.918 0.949 0.943 0.895 0.898 0.882 D 0.025 0.013 0.000 0.025 0.027 0.013 0.014 0.000 0.000 0.039 E 0.063 0.115 0.014 0.025 0.041 0.013 0.029 0.026 0.051 0.053 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.125 0.256 0.057 0.200 0.162 0.100 0.114 0.211 0.205 0.237 obs H 0.163 0.270 0.056 0.186 0.153 0.097 0.110 0.193 0.190 0.218 exp P-ext 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 75 Table 2. Continued Locus MA1 MA2 MA3 MA4 CA1 CA2 CA3 CA4 CA5 CA6 GPI N 34 37 37 36 40 38 40 19 39 38 A 0.000 0.000 0.000 0.014 0.013 0.013 0.013 0.000 0.013 0.026 B 0.147 0.257 0.324 0.305 0.262 0.435 0.312 0.368 0.231 0.275 C 0.059 0.041 0.081 0.028 0.000 0.026 0.013 0.000 0.077 0.053 D 0.720 0.648 0.567 0.611 0.712 0.500 0.637 0.605 0.628 0.632 E 0.015 0.000 0.014 0.000 0.000 0.000 0.000 0.026 0.013 0.000 F 0.059 0.054 0.014 0.042 0.013 0.026 0.025 0.000 0.038 0.014 G 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.441 0.378 0.514 0.556 0.400 0.605 0.400 0.684 0.564 0.553 obs H 0.452 0.509 0.566 0.530 0.423 0.560 0.495 0.497 0.544 0.521 exp P-ext 0.692 0.017 0.141 0.785 0.408 0.801 0.436 0.221 0.698 0.568 MPI N 40 40 40 40 39 40 37 20 40 37 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.087 0.112 0.100 0.063 0.103 0.075 0.095 0.075 0.075 0.176 C 0.913 0.888 0.900 0.937 0.897 0.912 0.905 0.925 0.925 0.824 D 0.000 0.000 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.000 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.125 0.225 0.200 0.125 0.154 0.175 0.189 0.150 0.150 0.297 obs H 0.160 0.200 0.180 0.117 0.184 0.162 0.171 0.138 0.139 0.290 exp P-ext 0.249 1.000 1.000 1.000 0.328 1.000 1.000 1.000 1.000 1.000 PGD N 36 35 34 30 37 34 37 20 38 37 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 C 0.958 0.957 0.926 0.884 0.986 0.975 0.932 0.950 0.961 0.918 D 0.042 0.029 0.059 0.083 0.000 0.000 0.027 0.025 0.000 0.014 E 0.000 0.014 0.015 0.033 0.014 0.015 0.041 0.025 0.039 0.068 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.083 0.086 0.147 0.233 0.027 0.059 0.135 0.100 0.079 0.162 obs H 0.080 0.083 0.138 0.212 0.027 0.058 0.126 0.096 0.076 0.151 exp P-ext 1.000 1.000 1.000 1.000 – 1.000 1.000 1.000 1.000 1.000 MDH N 40 38 40 36 35 38 40 20 37 34 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 C 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 D 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H – – – – – – – – – – obs H – – – – – – – – – – exp P-ext – – – – – – – – – – HBDH N 38 37 39 27 37 36 40 20 38 15 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.026 0.014 0.038 0.019 0.014 0.014 0.013 0.000 0.026 0.033 C 0.882 0.905 0.872 0.944 0.932 0.916 0.862 0.925 0.908 0.901 D 0.000 0.027 0.013 0.000 0.000 0.014 0.025 0.025 0.013 0.033 E 0.092 0.054 0.077 0.037 0.054 0.056 0.100 0.050 0.053 0.033 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H 0.237 0.189 0.256 0.111 0.135 0.167 0.225 0.150 0.158 0.200 obs H 0.214 0.176 0.232 0.106 0.127 0.156 0.245 0.141 0.172 0.187 exp P-ext 1.000 1.000 1.000 1.000 1.000 1.000 0.548 1.000 0.261 1.000 76 H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 Table 2. Continued Locus CV1 CV2 CV3 CV4 CV5 CV6 CV7 CV8 CV9 CV10 CV11 CV12 GPI N 38 38 40 40 40 39 40 39 40 40 40 34 A 0.026 0.039 0.038 0.025 0.013 0.013 0.038 0.026 0.025 0.038 0.025 0.015 B 0.316 0.158 0.273 0.274 0.200 0.244 0.400 0.474 0.325 0.250 0.450 0.397 C 0.026 0.132 0.013 0.000 0.050 0.038 0.000 0.026 0.000 0.000 0.000 0.015 D 0.566 0.579 0.613 0.650 0.652 0.615 0.562 0.397 0.550 0.612 0.474 0.544 E 0.013 0.066 0.025 0.013 0.050 0.064 0.000 0.026 0.025 0.000 0.013 0.000 F 0.053 0.013 0.038 0.038 0.025 0.013 0.000 0.051 0.075 0.075 0.038 0.029 G 0.000 0.013 0.000 0.000 0.013 0.013 0.000 0.000 0.000 0.025 0.000 0.000 H 0.605 0.533 0.475 0.575 0.500 0.462 0.425 0.641 0.550 0.550 0.575 0.353 obs H 0.576 0.616 0.546 0.500 0.532 0.556 0.522 0.621 0.585 0.555 0.570 0.553 exp P-ext 0.046 0.311 0.338 0.101 0.156 0.196 0.179 0.106 0.789 0.669 1.000 0.003 MPI N 33 37 36 38 40 39 40 40 38 40 40 40 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.076 0.054 0.056 0.053 0.138 0.115 0.038 0.063 0.066 0.125 0.075 0.125 C 0.924 0.946 0.944 0.947 0.862 0.885 0.962 0.925 0.934 0.875 0.913 0.875 D 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.013 0.000 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 F 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.000 H 0.091 0.108 0.111 0.105 0.175 0.231 0.075 0.150 0.132 0.200 0.175 0.250 obs H 0.140 0.102 0.105 0.100 0.237 0.204 0.072 0.140 0.123 0.219 0.162 0.219 exp P-ext 0.150 1.000 1.000 1.000 0.134 1.000 1.000 1.000 1.000 0.473 1.000 1.000 PGD N 39 39 40 37 33 39 40 37 38 39 40 39 A 0.000 0.013 0.013 0.014 0.000 0.000 0.000 0.000 0.000 0.000 0.013 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.026 C 0.923 0.923 0.961 0.904 0.970 1.000 0.925 0.878 0.881 0.911 0.974 0.910 D 0.000 0.000 0.000 0.041 0.015 0.000 0.000 0.027 0.066 0.000 0.000 0.013 E 0.026 0.013 0.013 0.041 0.015 0.000 0.025 0.041 0.000 0.038 0.013 0.051 F 0.051 0.051 0.013 0.000 0.000 0.000 0.050 0.054 0.053 0.051 0.000 0.000 H 0.103 0.154 0.075 0.135 0.061 – 0.150 0.135 0.184 0.179 0.050 0.154 obs H 0.145 0.145 0.073 0.177 0.059 – 0.141 0.223 0.216 0.167 0.049 0.168 exp P-ext 0.091 1.000 1.000 0.161 1.000 – 1.000 0.001 0.219 1.000 1.000 0.255 MDH N 40 39 40 40 40 39 40 40 40 40 40 40 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.000 C 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 D 1.000 1.000 1.000 0.987 1.000 1.000 1.000 0.987 1.000 1.000 1.000 1.000 E 0.000 0.000 0.000 0.000 0.013 0.000 0.000 0.000 0.000 0.000 0.000 0.000 H – – – 0.025 0.025 – – 0.025 – – – – obs H – – – 0.025 0.025 – – 0.025 – – – – exp P-ext – – – 1.000 1.000 – – 1.000 – – – – HBDH N 39 39 39 33 39 39 40 39 40 40 39 39 A 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 B 0.013 0.026 0.013 0.000 0.000 0.013 0.000 0.038 0.038 0.038 0.038 0.000 C 0.936 0.897 0.949 0.879 0.936 0.936 0.899 0.885 0.875 0.997 0.885 0.897 D 0.000 0.000 0.000 0.015 0.000 0.013 0.038 0.000 0.000 0.000 0.000 0.013 E 0.051 0.077 0.038 0.106 0.051 0.038 0.050 0.064 0.087 0.050 0.064 0.077 F 0.000 0.000 0.000 0.000 0.013 0.000 0.013 0.013 0.000 0.025 0.013 0.013 H 0.128 0.154 0.103 0.242 0.128 0.128 0.200 0.179 0.200 0.175 0.231 0.154 obs H 0.121 0.188 0.098 0.216 0.121 0.122 0.186 0.212 0.225 0.208 0.212 0.188 exp P-ext 1.000 0.328 1.000 1.000 1.000 1.000 1.000 0.046 0.047 0.208 1.000 0.328 H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 77 Fig. 1. Graphical representation of mean number of alleles per locus at each of the four archipelagos AZ 5Azores; MA5Madeira; CA5Canary Islands; CV5Cape Verde Islands. This difference was nearly significant P 50.0507 and therefore indicated a ‘‘ten- dency’’. In contrast, H did not differ significantly among the four archipelagos obs P 50.4826. All F indices were small, indicating no population differentiation at any xy of the three analysed hierarchical levels i.e. F 50.005; F 50.002; F ,0.001. PI IA AT After Bonferroni correction, eight significant allele frequency heterogeneities were detected when the archipelagos were compared: three i.e. GPI, PGD, HBDH among CV and AZ, two i.e. GPI, PGD among CV and MA, one i.e. PGD among CV and CA, one i.e. PGD among MA and CA, and one among AZ and MA i.e. PGD Table 3. The first axis of the correspondence analysis, which explained 33.19 of the variation, separated the CV from the remaining Macaronesian Islands. This axis mainly Table 3 a Exact tests of allele frequency heterogeneities, according to Guo and Thompson 1992 GPI MPI PGD MDH HBDH AZ–MA 0.05076 0.79000 0.00036 1.00000 0.42472 AZ–CA 0.84836 1.00000 0.27278 0.58522 0.41846 AZ–CV 0.00001 0.05454 0.00001 0.03950 0.00046 MA–CA 0.13578 0.84030 0.00102 – 0.79490 MA–CV 0.00136 0.71848 0.00026 1.00000 0.55006 CA–CV 0.02208 0.27440 0.00182 1.00000 0.26526 Significant after sequential Bonferroni correction. a AZ 5Azores; MA5Madeira; CA5Canary Islands; CV5Cape Verde Islands. 78 H . De Wolf et al. J. Exp. Mar. Biol. Ecol. 246 2000 69 –83 Fig. 2. Regression analysis of pairwise Nm estimates against pairwise geographical distances. expressed effects of PGD-F, GPI-A, GPI-E, and GPI-G. The second factor discriminated the MA from the other archipelagos, mainly on the basis of PGD-D and GPI-C. This factor explained only an additional 18.14 of the variation making it less informative. Both the regression analysis among pairwise Nm values and geographic distances Fig. 2 as well as a plot of private alleles based gene flow estimates on a geographic map of Macaronesia Fig. 3, were reminiscent of IBD. Hence, the highest Nm value was observed among MA and CA, the lowest among AZ and CV Fig. 3, Table 4.

4. Discussion