Evaluating Connectivity in the Brooding Brittle Star Astrotoma agassizii across the Drake Passage in the Southern Ocean
| Autor: | Rebecca L. Hunter, Kenneth M. Halanych |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Polar front
Marine biology geography geography.geographical_feature_category Base Sequence Ecology Continental shelf fungi Marine Biology Pelagic zone Biology biology.organism_classification Invertebrates Polymerase Chain Reaction Benthic zone Geographical distance Brittle star Genetics Animals Biological dispersal Molecular Biology Phylogeny Genetics (clinical) DNA Primers Biotechnology |
| Zdroj: | Journal of Heredity. 99:137-148 |
| ISSN: | 1465-7333 0022-1503 |
| Popis: | Studies examining population structure and genetic diversity of benthic marine invertebrates in the Southern Ocean have emerged in recent years. However, many taxonomic groups remain largely unstudied, echinoderms being one conspicuous example. The brittle star Astrotoma agassizii is distributed widely throughout Antarctica and southern South America. This species is a brooding echinoderm and therefore may have limited dispersal capacity. In order to determine the effect of hypothesized isolating barriers in the Southern Ocean, such as depth, geographic distance, and the polar front, 2 mitochondrial DNA markers were used to compare populations from the South American and Antarctic continental shelves. Astrotoma agassizii was shown to be genetically discontinuous across the polar front. In fact, populations previously assumed to be panmictic instead represent 3 separate lineages that lack morphological distinction. However, within lineages, genetic continuity was displayed across a large geographic range (>500 km). Therefore, despite lacking a pelagic larval stage, A. agassizii can disperse across substantial geographic distance within continental shelf regions. These results indicate that geographic distance alone may not be a barrier to dispersal, but rather the combined effects of distance, depth, and the polar front act to prevent gene flow between A. agassizii populations in the Southern Ocean. |
| Databáze: | OpenAIRE |
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