From: Introgressive hybridization and latitudinal admixture clines in North Atlantic eels
Author(s) | Year | Marker(s) | Sample Sizes (n) | Results | ||||
---|---|---|---|---|---|---|---|---|
Continental | Oceanic | |||||||
Europe | America | Iceland | Sargasso | Azores | ||||
Allozymes | ||||||||
Fine et al.[24] | 1964 | Transferrins* | 44 | 0 | 0 | 0 | 0 | Candidate markers for eel species differentiation: transferrins |
Fine et al.[25] | 1967 | Transferrins* | 142 | 104 | 0 | 0 | 0 | Heterogeneity among North Atlantic eels (not significant**) |
Sick et al.[26] | 1967 | Haemoglobin | 848 | 666 | 0 | 0 | 0 | Polymorphism in American eels only, monomorphy in European eels |
Pantelouris et al.[27] | 1970 | Transferrins* | 40 | 0 | 37 | 0 | 0 | Differentiation among European continental and Icelandic eels (significant**) |
Pantelouris et al.[28] | 1971 | Transferrins* | 0 | 63 | 96 | 0 | 0 | Differentiation among American continental and Icelandic eels (significant**) |
de Ligny & Pantelouris [20] | 1973 | MDH | 300 | 70 | 0 | 0 | 25 | First available diagnostic marker: MDH; |
Differentiation among American and European continental eels (significant**); | ||||||||
No differentiation among eels from Azores and Europe. | ||||||||
Williams et al.[29] | 1973 | ADH, PHI, SDH, MDH, EST | 0 | 735 | 0 | 0 | 0 | Latitudinal clines at three allozyme markers (MDH invariable) |
ADH & SDH clines establish at larval American eel stages | ||||||||
PHI cline establishes during freshwater residency of American eels | ||||||||
Koehn & Williams [30] | 1978 | ADH, PHI, SDH | 0 | n.d. | 0 | 0 | 0 | Latitudinal clines at SDH & PHI loci temporally stable |
ADH cline unstable and allele frequencies vary among years | ||||||||
Comparini & Rodinò [31] | 1980 | MDH-2 | 1079 | 696 | 0 | 126 | 0 | Evidence for two eel species at spawning grounds in the Sargasso Sea |
Williams et al.[32] | 1984 | MDH-2 | n.d. | n.d. | 241 | 0 | 0 | First indication of genetic hybrids in Iceland |
Avise et al.[12] | 1990 | MDH-2 | 0 | 0 | 197 | 0 | 0 | Evidence for an eel hybrid zone: cyto-nuclear disequilibrium in Iceland |
Maes & Volckaert [33] | 2002 | 12 loci | 304 | 0 | 0 | 0 | 0 | Evidence against panmixia in European eels: IBD (r =0.78; P = 0.030) |
Maes et al.[34] | 2006 | 12 loci | 840 | 0 | 172 | 0 | 0 | No interannual differentiation in European eels: no IBT (r = 0.0050, P > 0.05) |
Mitochondrial DNA | ||||||||
Avise et al.[21] | 1986 | RFLP | 29 | 109 | 0 | 0 | 0 | Strong evidence for two eel species in the North Atlantic |
Avise et al.[12] | 1990 | RFLP | 17 | 27 | 197 | 0 | 0 | Evidence for an eel hybrid zone: cyto-nuclear disequilibrium in Iceland |
Lintas et al.[35] | 1998 | D-loop | 55 | 0 | 0 | 0 | 0 | Extensive variability in European eels |
Daemen et al.[36] | 2001 | Cytb | 253 | 0 | 0 | 0 | 0 | Latitudinal haplotype diversity cline in European eels |
AFLP | ||||||||
Albert et al.[37] | 2006 | 373 fragments | 186 | 193 | 748 | 0 | 0 | Quantification of total fraction of hybrid eels in Iceland (15.5%); |
Latitudinal gradient of hybrid portions in Iceland; | ||||||||
Evidence for high portion of later generation hybrids (30%); | ||||||||
Indication of higher survival rates of hybrid eels in Iceland. | ||||||||
Gagnaire et al.[38] | 2009 | 373 fragments | 186 | 193 | 748 | 0 | 0 | Evidence for selection and non-neutral introgression |
Microsatellites | ||||||||
Daemen et al.[36] | 2001 | 5 loci | 107 | 0 | 0 | 0 | 0 | Low, significant genetic differentiation in European eels (F ST = 0.040; P < 0.050) |
Wirth & Bernatchez [39] | 2001 | 7 loci | 561 | 0 | 50 | 0 | 0 | Evidence against panmixia in European eels: IBD (r = 0.46; P < 0.0070); |
Low, significant genetic differentiation in European eels (F ST = 0.0017; P = 0.0014); | ||||||||
Genetic intermediacy of Icelandic eels among North Atlantic locations. | ||||||||
Wirth & Bernatchez [40] | 2003 | 7 loci | 561 | 402 | 50 | 0 | 0 | Evidence for long-term population decline in North Atlantic eels; |
Differentiation among North Atlantic eels (F ST = 0.018; P < 0.0010); | ||||||||
No evidence against panmixia in American eels: no IBD (r = 0.0030; P > 0.40). | ||||||||
Mank & Avise [41] | 2003 | 6 loci | 44 | 68 | 203 | 0 | 0 | Mild genetic differentiation among North Atlantic eels (G ST = 0.055; SE = 0.0049); |
Genetic intermediacy of Icelandic eels among North Atlantic locations. | ||||||||
Dannewitz et al.[42] | 2005 | 6 loci | 2566 | 0 | 60 | 0 | 0 | Temporal instability of IBD pattern in European eels; |
Low genetic differentiation in European eels (F ST = 0.0014; P < 0.010); | ||||||||
Temporal genetic variation exceeds geographic variation. | ||||||||
Maes et al.[34] | 2006 | 6 loci | 840 | 0 | 172 | 0 | 0 | Evidence for interannual differentiation in Europe: IBT (r = 0.18; P = 0.043); |
Contradicts allozyme pattern: no IBT, but IBD. | ||||||||
Palm et al.[43] | 2009 | 6 loci | 1210 | 0 | 0 | 0 | 0 | No genetic differentiation among same-aged silvering eels between a northern and a southern European locality (F ST = −0.00003; P =0.61); |
Als et al.[44] | 2011 | 21 loci | 0 | 0 | 0 | 388 | 0 | No evidence against panmixia in American or European leptocephali |
(F ST = 0.00019, P = 0.4755): no IBD, nor IBT; | ||||||||
Evidence for inter-species hybridization in the Sargasso Sea | ||||||||
Côté et al.[45] | 2013 | 18 loci | 0 | 2142 | 0 | 0 | 0 | No evidence against panmixia in the American eel (F ST = 0.00009; P = 0.998); |
Effective population size for American eels: N E =10 532 (CI95%: 9 312–11 752) |