MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
artículos
Título:
Phylogeography and genetic structure of two Patagonian shag species (Aves: Phalacrocoracidae)
Autor/es:
CALDERON, P. L.; QUINTANA, F.; CABANNE S.; LOUGHEED, S. C.; TUBARO, P. L.
Revista:
MOLECULAR PHYLOGENETICS AND EVOLUTION
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 72 p. 42 - 53
ISSN:
1055-7903
Resumen:
We compared the phylogeographic and genetic structure of two sympatric
shag species, Phalacrocorax magellanicus (rock shag) and Phalacrocorax atriceps
(imperial shag), from Patagonia (southern South America). We used multilocus
genotypes of nuclear DNA (microsatellite loci) from 324 individuals and mitochondrial
DNA sequences (ATPase) from 177 individuals, to evaluate hypotheses related to
the effect of physical and non-physical barriers on seabird evolution. Despite
sharing many ecological traits, the focal species strongly differ in two key
aspects: P. magellanicus has a strong tendency to remain at/near their breeding
colonies during foraging trips and the non-breeding season, while P. atriceps exhibits
the converse pattern. Both species showed similar mtDNA genetic structure,
where colonies from the Atlantic Coast, Pacific Coast and Fuegian region were
genetically divergent. We also found similarities in the results of Bayesian
clustering analysis of microsatellites, with both species having four clusters.
However population differentiation (e.g. Fst, Ust) was higher in P.
magellanicus compared to P. atriceps, and average membership probabilities of
individuals to specific clusters (Q-values) were also higher in the former. Phalacrocorax
magellanicus has strong phylogeographic structure, consistent with the impact
of Pleistocene glaciations, with diagnostic haplotypes associated with each of
the three mentioned regions. The same pattern was not as evident for P.
atriceps. Migration rate estimators were higher for P. atriceps than for P.
magellanicus; however both species followed an n-island-like model of gene
flow, this implies thatdispersal occurs
across the continental land mass that separates Atlantic and Pacific Oceans.
Our results supported the hypothesis that non-physical barriers are important
drivers of the genetic and phylogeographic structure in seabirds, and also that
physical barriers constitute effective but not absolute impediments to gene
flow.