36
Michelle Waycott, Gabriele Procaccini, Donald H. Les and Thorsten B. H. Reusch
Table 2. Seagrass population genetic studies. The aim of each study has been classified as either: W = within population
genetic diversity, B = between population genetic diversity, MS = mating system analysis, T = marker development, R =
restoration studies.
Study species
Methodology
Study aim
References
Amphibolis antarctica
Allozymes, DNA fing.
W, B
1
A. griffithii
Allozymes, DNA fing.
W, B
1
Cymodocea nodosa
RAPD, SSR
W, T
2–5
Halodule wrightii
RAPD
W, B
6
Halophila decipiens
RAPD
W, B
7
H. engelmannii
RAPD
W, B
7
H. hawaiiana
SSR
B
8
H. johnsonii
RAPD
W, B
7,9
H. stipulacea
RAPD, DNA seq.
W, B
10–11
Posidonia australis
Allozymes, RAPD
W, B, MS
12–15
P. coriacea
Allozymes,
W
16
P. oceanica
Allozymes, RAPD, SSR, DNA fing.
W, B, T, R, MS
17–33
Thalassia testudinum
RAPD
W, B
34–37
Thalassodendron ciliatum
RAPD
W, B
38
Zostera marina
Allozymes, DNA fing., SSR, DNA seq.
W, B, T, R, MS
39–64
Z. noltii
SSR
W, B, T
65–66
DNA fing. = multilocus DNA fingerprinting; RAPD = Randomly Amplified Polymorphic DNA; SSR = Simple Sequence
Repeats (microsatellites); DNA seq. = DNA sequencing.
1. Waycott et al. (1996); 2. Alberto et al. (2001); 3. Alberto et al. (2003b); 4. Procaccini and Mazzella (1996); 5. Ruggiero et al.
(in press) 6. Angel (2002); 7. Jewett-Smith et al. (1997); 8. McDermid et al. (2003); 9. Freshwater et al. (2003); 10. Procaccini
et al. (1999a); 11. Ruggiero and Procaccini (2004); 12. Waycott (1995); 13. Waycott et al. (1997); 14. Waycott and Sampson
(1997); 15. Waycott (1998); 16. Campey et al. (1999); 17. Alberto et al. (2003a); 18. Capiomont et al. (1996); 19. Dalmazio
et al. (2002); 20. Franconi and Barcaccia (1995); 21. Jover et al. (2003); 22. Orsini et al. (2001); 23. Procaccini et al. (1996); 24.
Procaccini and Mazzella (1996); 25. Procaccini and Mazzella (1998); 26. Procaccini and Waycott (1998); 27. Procaccini et al.
(2000); 28. Procaccini et al. (2001); 29. Procaccini and Piazzi (2001); 30. Procaccini et al. (2002); 31. Raniello and Procaccini
(2002); 32. Ruggiero et al. (2002); 33. Sandmeier et al. (1999); 34. Kirsten et al. (1998); 35. Schlueter and Guttman (1998); 36.
Waycott and Barnes (2001); 37. Davis et al. (1999); 38. Bandeira and Nilsson (2001); 39. Alberte et al. (1994); 40. Billingham
et al. (2003); 41. de Heij and Nienhuis (1992); 42. Fain et al. (1992); 43. Gagnon et al. (1980); 44. H¨ ammerli and Reusch (2002);
45. H¨ ammerli and Reusch (2003a); 46. H¨ ammerli and Reusch (2003b); 47. H¨ ammerli and Reusch (2003c); 48. Laushman (1993);
49. Olsen et al. (2004); 50. Reusch et al. (1999a); 51. Reusch et al. (1999b); 52. Reusch et al. (1999c); 53. Reusch et al. (1999d);
54. Reusch (2000); 55. Reusch et al. (2000); 56. Reusch (2001a); 57. Reusch (2002); 58. Reusch (2003); 59. Ruckelshaus (1995);
60. Ruckelshaus (1996); 61. Ruckelshaus (1998); 62. Williams and Davis (1996); 63. Williams and Orth (1998); 64. Williams
(2001); 65. Coyer et al. (2004); 66. Coyer et al. (submitted).
For species level allozyme studies see also: McMillan (1981); (McMillan (1982) and McMillan (1991).
3. Posidonia oceanica
Contrasting levels of genetic diversity have also been
observed within the Mediterranean basin for the congeneric species P. oceanica. Studies have been conducted on 33 meadows sampled along the entire
distribution range of the species using microsatellite analysis. Overall genetic diversity seems to be
low [average Dg = 0.727; (Procaccini et al., 2001;
Procaccini et al., 2002)], with some identical genotypes present in different populations. Based on
the results from published studies, P. oceanica appears as a genetically depauperate species as result
of evolutionary processes or recent anthropogenic
influence.
Populations from the western basin were genetically more polymorphic than those from the eastern Mediterranean Sea, where North Adriatic meadows were represented by only one clone (Ruggiero
et al., 2002). Meadows are distinct genetically, with
overall θ = 0.451 (Nm θ = 0.304). A clear genetic sub-division seems to exist within the basin,
with the presence of three main groups representing
north-western, south-western, and eastern populations (Fig. 6). The existence of defined population
groups may result from processes acting on different time scales. Present surface circulation patterns
of surface currents may affect gene flow and/or colonization of different areas and could account for
the existence of genetic structure over the Mediterranean Sea as a whole. The genetic structure existing
in the Tyrrhenian Sea, with the presence of a clear
distinction between northern and southern populations (Ruggiero et al., 2002) (Fig. 6), reflects the
Michelle Waycott, Gabriele Procaccini, Donald H. Les and Thorsten B. H. Reusch
Table 2. Seagrass population genetic studies. The aim of each study has been classified as either: W = within population
genetic diversity, B = between population genetic diversity, MS = mating system analysis, T = marker development, R =
restoration studies.
Study species
Methodology
Study aim
References
Amphibolis antarctica
Allozymes, DNA fing.
W, B
1
A. griffithii
Allozymes, DNA fing.
W, B
1
Cymodocea nodosa
RAPD, SSR
W, T
2–5
Halodule wrightii
RAPD
W, B
6
Halophila decipiens
RAPD
W, B
7
H. engelmannii
RAPD
W, B
7
H. hawaiiana
SSR
B
8
H. johnsonii
RAPD
W, B
7,9
H. stipulacea
RAPD, DNA seq.
W, B
10–11
Posidonia australis
Allozymes, RAPD
W, B, MS
12–15
P. coriacea
Allozymes,
W
16
P. oceanica
Allozymes, RAPD, SSR, DNA fing.
W, B, T, R, MS
17–33
Thalassia testudinum
RAPD
W, B
34–37
Thalassodendron ciliatum
RAPD
W, B
38
Zostera marina
Allozymes, DNA fing., SSR, DNA seq.
W, B, T, R, MS
39–64
Z. noltii
SSR
W, B, T
65–66
DNA fing. = multilocus DNA fingerprinting; RAPD = Randomly Amplified Polymorphic DNA; SSR = Simple Sequence
Repeats (microsatellites); DNA seq. = DNA sequencing.
1. Waycott et al. (1996); 2. Alberto et al. (2001); 3. Alberto et al. (2003b); 4. Procaccini and Mazzella (1996); 5. Ruggiero et al.
(in press) 6. Angel (2002); 7. Jewett-Smith et al. (1997); 8. McDermid et al. (2003); 9. Freshwater et al. (2003); 10. Procaccini
et al. (1999a); 11. Ruggiero and Procaccini (2004); 12. Waycott (1995); 13. Waycott et al. (1997); 14. Waycott and Sampson
(1997); 15. Waycott (1998); 16. Campey et al. (1999); 17. Alberto et al. (2003a); 18. Capiomont et al. (1996); 19. Dalmazio
et al. (2002); 20. Franconi and Barcaccia (1995); 21. Jover et al. (2003); 22. Orsini et al. (2001); 23. Procaccini et al. (1996); 24.
Procaccini and Mazzella (1996); 25. Procaccini and Mazzella (1998); 26. Procaccini and Waycott (1998); 27. Procaccini et al.
(2000); 28. Procaccini et al. (2001); 29. Procaccini and Piazzi (2001); 30. Procaccini et al. (2002); 31. Raniello and Procaccini
(2002); 32. Ruggiero et al. (2002); 33. Sandmeier et al. (1999); 34. Kirsten et al. (1998); 35. Schlueter and Guttman (1998); 36.
Waycott and Barnes (2001); 37. Davis et al. (1999); 38. Bandeira and Nilsson (2001); 39. Alberte et al. (1994); 40. Billingham
et al. (2003); 41. de Heij and Nienhuis (1992); 42. Fain et al. (1992); 43. Gagnon et al. (1980); 44. H¨ ammerli and Reusch (2002);
45. H¨ ammerli and Reusch (2003a); 46. H¨ ammerli and Reusch (2003b); 47. H¨ ammerli and Reusch (2003c); 48. Laushman (1993);
49. Olsen et al. (2004); 50. Reusch et al. (1999a); 51. Reusch et al. (1999b); 52. Reusch et al. (1999c); 53. Reusch et al. (1999d);
54. Reusch (2000); 55. Reusch et al. (2000); 56. Reusch (2001a); 57. Reusch (2002); 58. Reusch (2003); 59. Ruckelshaus (1995);
60. Ruckelshaus (1996); 61. Ruckelshaus (1998); 62. Williams and Davis (1996); 63. Williams and Orth (1998); 64. Williams
(2001); 65. Coyer et al. (2004); 66. Coyer et al. (submitted).
For species level allozyme studies see also: McMillan (1981); (McMillan (1982) and McMillan (1991).
3. Posidonia oceanica
Contrasting levels of genetic diversity have also been
observed within the Mediterranean basin for the congeneric species P. oceanica. Studies have been conducted on 33 meadows sampled along the entire
distribution range of the species using microsatellite analysis. Overall genetic diversity seems to be
low [average Dg = 0.727; (Procaccini et al., 2001;
Procaccini et al., 2002)], with some identical genotypes present in different populations. Based on
the results from published studies, P. oceanica appears as a genetically depauperate species as result
of evolutionary processes or recent anthropogenic
influence.
Populations from the western basin were genetically more polymorphic than those from the eastern Mediterranean Sea, where North Adriatic meadows were represented by only one clone (Ruggiero
et al., 2002). Meadows are distinct genetically, with
overall θ = 0.451 (Nm θ = 0.304). A clear genetic sub-division seems to exist within the basin,
with the presence of three main groups representing
north-western, south-western, and eastern populations (Fig. 6). The existence of defined population
groups may result from processes acting on different time scales. Present surface circulation patterns
of surface currents may affect gene flow and/or colonization of different areas and could account for
the existence of genetic structure over the Mediterranean Sea as a whole. The genetic structure existing
in the Tyrrhenian Sea, with the presence of a clear
distinction between northern and southern populations (Ruggiero et al., 2002) (Fig. 6), reflects the