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7 - Phylogeography of coral reef fishes
- from PART II - PATTERNS AND PROCESSES
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- By Jeff A. Eble, University of West Florida, Brian W. Bowen, University of Hawaiʿi, Kaneohe, Giacomo Bernardi, University of California
- Edited by Camilo Mora, University of Hawaii, Manoa
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- Book:
- Ecology of Fishes on Coral Reefs
- Published online:
- 05 May 2015
- Print publication:
- 23 April 2015, pp 64-75
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Summary
The field of phylogeography seeks to shed light on the ecology and evolution of organisms by resolving genetic relationships across a geographic range. This includes comparisons among isolated populations, subspecies partitions, sister species, and more ancient separations. The staple method employed in phylogeographic studies has been mitochondrial DNA sequencing; however, the field has kept abreast of technical developments, with nuclear DNA sequencing and microsatellite fragment analysis now commonly used to resolve genetic patterns, and single nucleotide polymorphisms (SNPs) and next-generation sequencing technologies becoming increasingly popular. This review is focused on the contributions phylogeography has made to understanding reef fish dispersal, evolutionary divergence, and conservation. Examples of these findings include the following: (1) genetic surveys of reef fishes often reveal multiple evolutionary lineages within a species' range; (2) genetic connectivity by larval transport can vary from a few kilometers in anemone fishes, to entire ocean basins in unicorn fishes and other species with long larval stages; (3) biogeographic provinces, defined by species distributions, are often concordant with genetic partitions for widespread species; (4) new species arise in biodiversity hotspots like the Coral Triangle and Caribbean Sea, but these areas can also accumulate species that originate in peripheral oceanic islands; (5) both biodiversity hotspots and peripheral areas of high endemism should be conservation priorities; and (6) parentage analyses with “DNA fingerprints” show that some larvae settle close to their origin, reinforcing the conservation value of marine protected areas (MPAs). We conclude with a discussion of how rapidly developing methods for genomic sequencing are revolutionizing the field, allowing for the first time an in-depth exploration of the ecological and environmental factors that influence genomes, and the genetic building blocks for future biodiversity.
The field of phylogeography incorporates elements of phylogenetics (species trees), biogeography (species distributions), and population genetics [115]. Roots of this field can be found in the first biochemical comparisons of organisms, most commonly with the technique of protein electrophoresis [46]. In a classic application of this technique, seemingly identical bonefishes (Albula spp.) caught in the same location in Hawaiʿi were found to include two species [2307].
Molecular evidence for cryptic species among the Antarctic fish Trematomus bernacchii and Trematomus hansoni
- Giacomo Bernardi, Usha Goswami
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- Journal:
- Antarctic Science / Volume 9 / Issue 4 / December 1997
- Published online by Cambridge University Press:
- 10 May 2004, pp. 381-385
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The notothenid species Trematomus bernacchii has previously been shown, by allozyme analysis, to be a complex of two cryptic species, one of which being more closely related to T. hansoni than to the other T. bernacchii cryptic species. Two T. bernacchii colour morphs, “white blotch” and “brown”, at McMurdo Sound, may correspond to these cryptic species. In this study, we present mitochondrial DNA sequences of the 12S and 16S ribosomal regions for six “white blotch” morphs, eight “brown” morphs collected in McMurdo Sound, one individual collected off the Antarctic Peninsula, and two T. hansoni individuals from McMurdo Sound. These sequences were compared with those of T. bernacchii and T. hansoni in the literature. Based on 14 phylogenetically informative sequences, no differences were found between “white blotch” and “brown” morphs. Furthermore, only one substitution separated these sequences from the previously published T. hansoni sequence, while 10 substitutions separated them from the previously published T. bernacchii sequence. Misidentified specimens, and sequence misreadings may be at the origin of these discrepancies. However, the presence of cryptic species within T. bernacchii and T. hansoni is not ruled out.