Microsatellite allele sizes alone are insufficient to delineate species boundaries inSymbiodinium
| Autor: | Bette L. Willis, M. J. H. van Oppen, Line K. Bay, Emily J. Howells |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
0301 basic medicine Genetic diversity education.field_of_study Ecology Population Population genetics Biology biology.organism_classification 010603 evolutionary biology 01 natural sciences 03 medical and health sciences Symbiodinium 030104 developmental biology Evolutionary biology Genetic marker Genetic structure Genetics Microsatellite Allele education Ecology Evolution Behavior and Systematics |
| Zdroj: | Molecular Ecology. 25:2719-2723 |
| ISSN: | 0962-1083 |
| Popis: | Symbiodinium are a diverse group of unicellular dinoflagellates that are important nutritional symbionts of reef-building corals. Symbiodinium putative species ('types') are commonly identified with genetic markers, mostly nuclear and chloroplast encoded ribosomal DNA regions. Population genetic analyses using microsatellite loci have provided insights into Symbiodinium biogeography, connectivity and phenotypic plasticity, but are complicated by: (i) a lack of consensus criteria used to delineate inter- vs. intragenomic variation within species; and (ii) the high density of Symbiodinium in host tissues, which results in single samples comprising thousands of individuals. To address this problem, Wham & LaJeunesse (2016) present a method for identifying cryptic Symbiodinium species from microsatellite data based on correlations between allele size distributions and nongeographic genetic structure. Multilocus genotypes that potentially do not recombine in sympatry are interpreted as secondary 'species' to be discarded from downstream population genetic analyses. However, Symbiodinium species delineations should ideally incorporate multiple physiological, ecological and molecular criteria. This is because recombination tests may be a poor indicator of species boundaries in Symbiodinium due to their predominantly asexual mode of reproduction. Furthermore, discontinuous microsatellite allele sizes in sympatry may be explained by secondary contact between previously isolated populations and by mutations that occur in a nonstepwise manner. Limitations of using microsatellites alone to delineate species are highlighted in earlier studies that demonstrate occasional bimodal distributions of allele sizes within Symbiodinium species and considerable allele size sharing among Symbiodinium species. We outline these issues and discuss the validity of reinterpretations of our previously published microsatellite data from Symbiodinium populations on the Great Barrier Reef (Howells et al. 2013). |
| Databáze: | OpenAIRE |
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