Population genetic analyses of Hypoplectrus coral reef fishes provide evidence that local processes are operating during the early stages of marine adaptive radiations
ABSTRACT Large-scale, spatially explicit models of adaptive radiation suggest that the spatial genetic structure within a species sampled early in the evolutionary history of an adaptive radiation might be higher than the genetic differentiation between different species formed during the same radiation over all locations. Here we test this hypothesis with a spatial population genetic analysis of Hypoplectrus coral reef fishes (Serranidae), one of the few potential cases of a recent adaptive radiation documented in the marine realm. Microsatellite analyses of Hypoplectrus puella (barred hamlet) and Hypoplectrus nigricans (black hamlet) from Belize, Panama and Barbados validate the population genetic predictions at the regional scale for H. nigricans despite the potential for high levels of gene flow between populations resulting from the 3-week planktonic larval phase of Hypoplectrus. The results are different for H. puella, which is characterized by significantly lower levels of spatial genetic structure than H. nigricans. An extensive field survey of Hypoplectrus population densities complemented by individual-based simulations shows that the higher abundance and more continuous distribution of H. puella could account for the reduced spatial genetic structure within this species. The genetic and demographic data are also consistent with the hypothesis that H. puella might represent the ancestral form of the Hypoplectrus radiation, and that H. nigricans might have evolved repeatedly from H. puella through ecological speciation. Altogether, spatial genetic analysis within and between Hypoplectrus species indicate that local processes can operate at a regional scale within recent marine adaptive radiations.
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ABSTRACT: The radiation of surfperches (Embiotocidae) in the temperate North Pacific has been suggested to be the product of ecological competition and niche partitioning. Surfperches are a family of viviparous marine fishes, which have been used to study multiple paternity, sperm competition, and population genetics. Phylogenetic inference is essential for interpreting the evolutionary context of embiotocid life history traits and testing alternative scenarios, yet previous studies have yielded phylogenies with low support and incongruent topologies. Here we constructed reduced representation genomic libraries using restriction-site associated DNA (RAD) sequence markers to infer phylogenetic relationships among all genera and 22 out of 24 embiotocid species. Orthologous markers retained across 91% of sampled species, corresponding to 523 loci, yielded trees with the highest support values. Our results support a scenario where embiotocids first diverged into clades associated with sandy and reef habitats during the middle Miocene (13-18 Mya) with subsequent invasions of novel habitats in the reef associated clade, and northern range expansion in the Northwest Pacific. The appearance of California kelp forests (Laminariales) in the late Miocene (8 - 15 Mya) correlates with further proliferation in the reef associated clade. In all cases, radiations occurred within specific habitats, a pattern consistent with niche partitioning. We infer fine scale species relationships among surfperches with confidence and corroborate the utility of RAD data for phylogenetic inference in young lineages. Copyright © 2015. Published by Elsevier Inc.Molecular Phylogenetics and Evolution 04/2015; 88. DOI:10.1016/j.ympev.2015.03.027 · 4.02 Impact Factor
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ABSTRACT: Fishes constitute about half of all known vertebrate species and have colonized nearly all available marine and freshwater habitats. The greatest diversity of fishes is found in the marine realm as well as in large (and often old) freshwater lakes such as the East African Great Lakes. Here, we compare the phylogeographic history of fishes in marine and large freshwater ecosystems, with particular emphasis on groups that underwent adaptive radiation, i.e. the emergence of a multitude of species from a single ancestor as a consequence of the adaptation to different ecological niches. Phylogeographic analyses are highly suited to identify and compare causal agents of speciation in rapidly diversifying groups. This is particularly true for fishes, in which distribution ranges and preferred habitat structures can be quantified in a straightforward matter.
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ABSTRACT: Connectivity levels among Brazilian reef fish fauna populations have attracted growing interest, mainly between mainland shores and oceanic islands. The Pomacentridae, whose phylogeographic patterns are largely unknown in the Atlantic, are a family of dominant fish in reef regions. We present data on the variability and population structure of damselfish Chromis multilineata in different areas along the northeast coast of Brazil and in the waters around the oceanic islands of Fernando de Noronha (FNA) and Saint Peter and Saint Paul Archipelago (SPSPA) through analysis of the HVR1 mtDNA sequence of the control region. The remote SPSPA exhibits the highest level of genetic divergence among populations.Conventional andmolecular cytogenetic analysis showed similar karyotype patterns (2n = 48 acrocentrics) between these insular areas. Our estimates reveal three genetically different population groups of C. multilineata on the Brazilian coast. The level of genetic structure is higher than previous data suggested, indicating complex panel of interactions between the oceanic island and coastal populations of Brazil.BioMed Research International 10/2014; 2014(254698):11. DOI:10.1155/2014/254698 · 2.71 Impact Factor