Table 1.
Taxonomic and population sampling of Galápagos giant tortoises, genetic diversity at DNA sequence (mtCR and PAX1P1) and 12 microsatellite (msat) loci, and comparison of census (Nc) and effective population size (Ne) from NeESTIMATOR analyses. Sample size is the number of individuals assayed for variation. Nhap is the number of different haplotypes detected in each population sample; Hd is haplotypic diversity, AR is mean allelic richness, and HE is expected heterozygosity. All Ne and Nc values relate to the previous generation, assuming a 25-year generation time. PE is a point estimate. To calculate the Ne:Nc ratio, the midpoint of the range of Nc values reported by MacFarland et al. (1974) was used as the Nc point estimate. The range of the Ne:Nc ratio is the most extreme upper and lower values for this ratio
| Species | Population | Sample size | DNA sequence diversity | msat diversity | Nc1 | Ne | Ne:Nc | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PAX1P1 | mtCR | msat | PAX1P1 | mtCR | AR | HE | 1965–1972 | PE (95% CI) | PE (range) | ||||
| Nhap | Hd | Nhap | Hd | ||||||||||
| Chelonoidis hoodensis | ESP | 15 | 15 | 15 | 3 | 0.54 | 1 | – | 2.64 | 0.49 | 20–30 | 15 (6, 79) | 0.61 (0.20, 3.95) |
| Chelonoidis chathamensis | SCR | 17 | 19 | 19 | 4 | 0.41 | 1 | – | 5.39 | 0.73 | 500–700 | 68 (32, 4592) | 0.11 (0.05, 9.18) |
| Chelonoidis porteri | RES | 22 | 23 | 25 | 5 | 0.36 | 7 | 0.82 | 8.25 | 0.75 | 2000–3000 | 78 (45, 220) | 0.03 (0.02, 0.11) |
| Chelonoidis sp. nov. | CF | 13 | 20 | 21 | 4 | 0.29 | 2 | 0.10 | 3.83 | 0.54 | 50–100 | 14 (8, 27) | 0.19 (0.08, 0.54) |
| Chelonoidis ephippium | PZ | 21 | 27 | 24 | 4 | 0.26 | 13 | 0.88 | 5.93 | 0.67 | 150–200 | 26 (17, 45) | 0.15 (0.09, 0.30) |
| Chelonoidis darwini | AGO | 15 | 21 | 22 | 4 | 0.41 | 8 | 0.83 | 7.39 | 0.80 | 500–700 | 14 (11, 18) | 0.02 (0.02, 0.04) |
| Chelonoidis microphyes | VD | 19 | 21 | 21 | 3 | 0.50 | 2 | 0.50 | 4.81 | 0.67 | 500–1000 | 38 (21, 108) | 0.05 (0.02, 0.22) |
| Chelonoidis vandenburghi | VA | 25 | 28 | 24 | 4 | 0.46 | 5 | 0.33 | 5.46 | 0.67 | 3000–5000 | 102 (41, ∞) | 0.03 (0.01, ∞) |
| Chelonoidis guntheri | CAZ | 10 | 22 | 23 | 1 | – | 2 | 0.37 | 4.96 | 0.63 | 200–300 | 45 (25, 146) | 0.18 (0.08, 0.73) |
| Chelonoidis guntheri | RU | 10 | 18 | 17 | 3 | 0.43 | 3 | 0.54 | 6.73 | 0.75 | 100–200 | 28 (18, 48) | 0.37 (0.18, 0.96) |
| Chelonoidis guntheri | CR | 9 | 22 | 22 | 3 | 0.52 | 7 | 0.79 | 6.04 | 0.75 | J | 19 (14, 28) | 0.26 (0.14, 0.56) |
| Chelonoidis vicina | ECA | 22 | 29 | 29 | 3 | 0.38 | 6 | 0.42 | 6.79 | 0.76 | 400–600 | 42 (31, 65) | 0.17 (0.10, 0.33) |
| Chelonoidis vicina | WCA | 21 | 25 | 28 | 5 | 0.60 | 7 | 0.80 | 5.15 | 0.71 | J | 25 (17, 41) | 0.10 (0.06, 0.21) |
| Chelonoidis becki | PBL | 9 | 18 | 22 | 1 | – | 2 | 0.21 | 6.46 | 0.76 | 1000–2000 | 20 (16, 27) | 0.03 (0.02, 0.05) |
| Chelonoidis becki | PBR | 15 | 27 | 29 | 3 | 0.43 | 1 | – | 5.49 | 0.70 | J | 38 (24, 77) | 0.05 (0.02, 0.15) |
Nc values are from MacFarland et al. (1974); populations that contributed to the Nc value listed on the row above are marked with “J” (joint estimate; e.g., ECA + WCA = 400 to 600).