Assortative mating as a barrier to gene flow in a coral reef fish species flock
- UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
- Felipe S. Barreto (Creator)
- Institution
- The University of North Carolina Wilmington (UNCW )
- Web Site: http://library.uncw.edu/
Abstract: While the only two recognized marine species flocks, the Pacific rockfishes and Antarctic
icefishes, show marked morphological distinctions coupled with obscure genetic relationships
due to their rapid radiation, the diversification of these flocks is believed to be very ancient
(several millions of years before present). In contrast, the hamlets, Caribbean reef fishes of the
genus Hypoplectrus (Serranidae), though highly differentiated with respect to their color
patterns, do not show monophyletic relationships in mtDNA sequences and are monomorphic in
several allozyme loci. Field observations show that mating is strongly assortative with regard to
color pattern in sympatric Hypoplectrus species in reefs off Panama and Jamaica. In order to
determine the strength of assortative mating and genetic differentiation in natural populations of
the previously unstudied Florida Keys Hypoplectrus species, field surveys were conducted at
several reefs and Amplified Fragment Length Polymorphisms were assayed in DNA of
specimens collected at the study sites. Hamlet populations in the Upper and Middle Keys were
composed mainly of blue (H. gemma, 23%) and butter (H. unicolor, 63%) hamlets, with black
(H. nigricans) and barred (H. puella) hamlets present at low frequencies. Observation of 68
mating pairs suggested very strong assortative mating, with only mixed pair witnessed. Genetic
distances between blue and butter hamlets, estimated from band sharing indeces based on 1108
DNA fragments, resulted in random clustering of individuals, with no monophyly according to
color patterns. One AFLP fragment, however, showed strong frequency differences between the
two morphospecies. This marker, coupled with the strong assortative mating observed, was
regarded as evidence of partial reproductive isolation between H. gemma and H. unicolor. The
lack of overall genomic differentiation thus suggested that the radiation of the 11 morphospecies
of Hypoplectrus was recent and did not yet reflect species boundaries. The hamlet radiation is a unique example of marine incipient speciation.
Assortative mating as a barrier to gene flow in a coral reef fish species flock
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Additional Information
- Publication
- Thesis
- A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science
- Language: English
- Date: 2009
- Keywords
- Coral reef ecology, Coral reef fishes--Morphology-- Florida--Florida Keys, Coral reef fishes--Variation --Florida--Florida Keys
- Subjects
- Coral reef fishes -- Morphology -- Florida -- Florida Keys
- Coral reef fishes -- Variation -- Florida -- Florida Keys
- Coral reef ecology