Artículos de revistas
Evidence for nonallopatric speciation among closely related sympatric Heliotropium species in the Atacama Desert
Fecha
2014Registro en:
Ecology and Evolution 2013; 4(3): 266– 275
DOI: 10.1002/ece3.929
Autor
Luebert Bruron, Federico José
Jacobs, Pit
Hilger, Hartmut
Muller, Ludo A.
Institución
Resumen
The genetic structure of populations of closely related, sympatric species may
hold the signature of the geographical mode of the speciation process. In fully
allopatric speciation, it is expected that genetic differentiation between species
is homogeneously distributed across the genome. In nonallopatric speciation,
the genomes may remain undifferentiated to a large extent. In this article, we
analyzed the genetic structure of five sympatric species from the plant genus
Heliotropium in the Atacama Desert. We used amplified fragment length polymorphisms
(AFLPs) to characterize the genetic structure of these species and
evaluate their genetic differentiation as well as the number of loci subject to
positive selection using divergence outlier analysis (DOA). The five species form
distinguishable groups in the genetic space, with zones of overlap, indicating
that they are possibly not completely isolated. Among-species differentiation
accounts for 35% of the total genetic differentiation (FST = 0.35), and FST
between species pairs is positively correlated with phylogenetic distance. DOA
suggests that few loci are subject to positive selection, which is in line with a
scenario of nonallopatric speciation. These results support the idea that sympatric
species of Heliotropium sect. Cochranea are under an ongoing speciation
process, characterized by a fluctuation of population ranges in response to
pulses of arid and humid periods during Quaternary times.