Name: | Description: | Size: | Format: | |
---|---|---|---|---|
569.33 KB | Adobe PDF |
Advisor(s)
Abstract(s)
We explore the phylogeography of the broadcast
spawner Marthasterias glacialis along south Europe
and Azores. Sequences of the cytochrome c oxidase gene
from 225 specimens, belonging to 10 localities, were
analysed. We found 73 haplotypes grouped within two
lineages (divergence 2.9%). One lineage was Atlanto–
Mediterranean, whereas another one was exclusively
Mediterranean. Estimation of lineages split goes back to
830,000–580,000 (±120,000) years ago. This suggests that
sea-level oscillations during the Pleistocene glaciations
promoted gene flow interruption, lineage divergence
between basins and cryptic speciation. Secondary contact
between populations allowed a recolonization of the
Mediterranean by the Atlantic lineage. When animals of
the Atlanto–Mediterranean lineage were considered separately,
Fst index and AMOVA did not show significant
differences between populations along either the Iberian
Peninsula or basins. Isolation by distance between populations
was not detected, and only populations of Plymouth
and Azores showed significant differences to all the others.
The remoteness of Azores islands might explain the
structure of this population. Haphazard arrival of larvae
and local extinctions rather than contemporary restricted
gene flow might be responsible for the distinctive population
structure of Plymouth.
Description
Keywords
Citation
Marine Biology, 157, 2015-2028