TY - JOUR
T1 - Genetic divergence of peripherally disjunct populations of the gastropod Batillariella estuarina in the Houtman Abrolhos Islands, Western Australia
AU - Pudovskis, M.S.
AU - Johnson, Michael
AU - Black, Robert
PY - 2001
Y1 - 2001
N2 - Geographically disjunct populations are unusual in marine species, but the Houtman Abrolhos Islands, Western Australia, provide opportunities to study highly disjunct peripheral isolates of several species. The intertidal snail Batillariella estuarina occurs in isolated tidal ponds in the Abrolhos Islands, where it is at its northern limit, disjunct from mainland populations by 600-900 km. The species is thus disjunct both geographically and among the peripherally isolated populations in the Abrolhos Islands. Comparisons of allozymes at 11 polymorphic loci were made among populations from 10 ponds in the Abrolhos Islands and six sites from relatively continuous tidal flats at Albany, 900 km away, the nearest major set of populations. Among all 16 populations, subdivision was high (F-ST = 0.455). Although there were subtle differences between the geographical regions, the large majority of divergence occurred among the isolated ponds in the Abrolhos (F-ST = 0.441), and divergence on the tidal flats at Albany was only moderate (F-ST = 0.085). Characteristic of peripheral isolates, the pond populations have less polymorphism and fewer alleles than the more connected populations at Albany. Combined with evidence of genetic divergence in the gastropods Bembicium vittatum and Austrocochlea constricta, which have very similar geographical distributions to that of B. estuarina, these results indicate the potential evolutionary significance of peripherally isolated marine polpulations in the unusual habitats of the Abrolhos Islands.
AB - Geographically disjunct populations are unusual in marine species, but the Houtman Abrolhos Islands, Western Australia, provide opportunities to study highly disjunct peripheral isolates of several species. The intertidal snail Batillariella estuarina occurs in isolated tidal ponds in the Abrolhos Islands, where it is at its northern limit, disjunct from mainland populations by 600-900 km. The species is thus disjunct both geographically and among the peripherally isolated populations in the Abrolhos Islands. Comparisons of allozymes at 11 polymorphic loci were made among populations from 10 ponds in the Abrolhos Islands and six sites from relatively continuous tidal flats at Albany, 900 km away, the nearest major set of populations. Among all 16 populations, subdivision was high (F-ST = 0.455). Although there were subtle differences between the geographical regions, the large majority of divergence occurred among the isolated ponds in the Abrolhos (F-ST = 0.441), and divergence on the tidal flats at Albany was only moderate (F-ST = 0.085). Characteristic of peripheral isolates, the pond populations have less polymorphism and fewer alleles than the more connected populations at Albany. Combined with evidence of genetic divergence in the gastropods Bembicium vittatum and Austrocochlea constricta, which have very similar geographical distributions to that of B. estuarina, these results indicate the potential evolutionary significance of peripherally isolated marine polpulations in the unusual habitats of the Abrolhos Islands.
U2 - 10.1046/j.0962-1083.2001.01398.x
DO - 10.1046/j.0962-1083.2001.01398.x
M3 - Article
SN - 0962-1083
VL - 10
SP - 2605
EP - 2616
JO - Molecular Ecology
JF - Molecular Ecology
ER -