IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
artículos
Título:
Deep phylogeographic divergence among populations of limpet Siphonaria lessoni on the east and west coasts of South America (aceptado)
Autor/es:
NUÑEZ, J.; FERNÁNDEZ IRIARTE P.; OCAMPO E.; IUDICA C.; CLEDÓN M.
Revista:
MARINE BIOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2015 vol. 162 p. 595 - 605
ISSN:
0025-3162
Resumen:
The historical processes that have influenced the genetic structure of
many species are often associated with environmental changes of the
Pleistocene glacial cycles. These climate changes involve temperature
oscillation, marine currents and loss of coastal habitats, which could
have affected the abundance and geographic distribution of marine
species in temperate coastal habitats. In this work, a 552-bp mtDNA fragment of COI locus of 92 individuals was sequenced to analyze the genetic structure of the limpet Siphonaria lessoni.
Individuals were collected on the intertidal coast of the Southern
Atlantic (Mar del Plata, San Antonio Oeste, Puerto Madryn and Ushuaia in
Argentina) and the Southern Pacific (Valdivia and Valparaíso in Chile).
S. lessoni displayed two distinct lineages
that were nearly reciprocally monophyletic between the Atlantic and
Pacific coasts. AMOVA tests revealed the existence of strong population
genetic structure. The Pacific coasts yielded more haplotypes and
polymorphic sites as well as higher haplotype and nucleotide diversity
than the Atlantic clade did. Both Tajima?s D and Fu?s F s
were significant and negative, suggesting that limpet populations are
in population expansion or have recently expanded. Accordingly, the
haplotype network for each clade showed a star-like phylogeographic
pattern. From IMa analysis, the divergence time between Pacific and
Atlantic populations was 100,000?1,000,000 ybp with gene flow occurring
from Pacific to Atlantic populations. The Bayesian Skyline analysis
revealed an older coalescence in the Pacific clade (30,000?300,000 ybp)
as compared to that in the Atlantic clade (4,000?40,000 ybp). This work
reports evidence of Pacific?Atlantic geographic isolation with
asymmetric migration, which is probably related to changes in sea level
and temperature due to the extended glaciation periods that occurred in
the region throughout the Pleistocene.