Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean
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 wid...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.421.1255 2023-05-15T13:49:23+02:00 Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean Rebecca L. Hunter Kenneth M. Halanych The Pennsylvania State University CiteSeerX Archives 2008 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.421.1255 en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.421.1255 Metadata may be used without restrictions as long as the oai identifier remains attached to it. text 2008 ftciteseerx 2016-01-08T04:02:02Z 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. Oceanographic current patterns and life-history traits, such as reproductive strategy, have been shown to directly affect Text Antarc* Antarctic Antarctica Drake Passage Southern Ocean Unknown Antarctic Drake Passage Southern Ocean |
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description |
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. Oceanographic current patterns and life-history traits, such as reproductive strategy, have been shown to directly affect |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Rebecca L. Hunter Kenneth M. Halanych |
spellingShingle |
Rebecca L. Hunter Kenneth M. Halanych Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean |
author_facet |
Rebecca L. Hunter Kenneth M. Halanych |
author_sort |
Rebecca L. Hunter |
title |
Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean |
title_short |
Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean |
title_full |
Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean |
title_fullStr |
Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean |
title_full_unstemmed |
Evaluating connectivity in the brooding brittle star Astrotoma agassizii across the Drake Passage in the Southern Ocean |
title_sort |
evaluating connectivity in the brooding brittle star astrotoma agassizii across the drake passage in the southern ocean |
publishDate |
2008 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.421.1255 |
geographic |
Antarctic Drake Passage Southern Ocean |
geographic_facet |
Antarctic Drake Passage Southern Ocean |
genre |
Antarc* Antarctic Antarctica Drake Passage Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Drake Passage Southern Ocean |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.421.1255 |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766251277049659392 |