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Advisor(s)
Abstract(s)
Extreme conditions of coastal lagoons could directly modify the genetic patterns of species.
The aim of this work was to investigate the influence of environmental conditions and
small scale dispersal patterns on the phosphoglucose isomerase (PGI*) genetic variability of
Cerastoderma glaucum from the Mar Menor coastal lagoon. For this purpose, 284 cockles
were collected around the perimeter of the lagoon. Vertical polyacrylamide gel electrophoresis
was used to scan for PGI* polymorphisms, giving a total of seven alleles. The
spatial genetic distribution of the PGI* variability, which seems to be marked by the main
circulation in the lagoon, discriminates four hydrological basins. In the central basin,
a gradient of allelic composition reflects the circulation forced by the dominant winds and
the main channel communicated to the open sea. This result is well supported by the
salinity GAM model that defines this gradient.
The other three basins are defined by the distribution of fine sand in a more complex
model that tries to explain the isolation of the three sites localized inside these basins. The
southern, western and northern basins show the lowest degree of interconnection and are
considered the most confined areas of the Mar Menor lagoon. This situation agrees with
the confinement theory for benthic assemblages in the lagoon. The greater degree of
differentiation seen in the Isla del Ciervo population is probably due to recent human
intervention on the nearby Marchamalo channel, which has been drained in recent years
thus altering the influence of the Mediterranean Sea on the southern basin.
Description
Keywords
Isozymes Principal component analysis Generalised additive models Synthesis maps Seascape genetics