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© 2017. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Herein, we use genetic data from 277 sleeper sharks to perform coalescent-based modeling to test the hypothesis of early Quaternary emergence of the Greenland shark (Somniosus microcephalus) from ancestral sleeper sharks in the Canadian Arctic-Subarctic region. Our results show that morphologically cryptic somniosids S. microcephalus and Somniosus pacificus can be genetically distinguished using combined mitochondrial and nuclear DNA markers. Our data confirm the presence of genetically admixed individuals in the Canadian Arctic and sub-Arctic, and temperate Eastern Atlantic regions, suggesting introgressive hybridization upon secondary contact following the initial species divergence. Conservative substitution rates fitted to an Isolation with Migration (IM) model indicate a likely species divergence time of 2.34 Ma, using the mitochondrial sequence DNA, which in conjunction with the geographic distribution of admixtures and Pacific signatures likely indicates speciation associated with processes other than the closing of the Isthmus of Panama. This time span coincides with further planetary cooling in the early Quaternary period followed by the onset of oscillating glacial-interglacial cycles. We propose that the initial S. microcephalusS. pacificus split, and subsequent hybridization events, were likely associated with the onset of Pleistocene glacial oscillations, whereby fluctuating sea levels constrained connectivity among Arctic oceanic basins, Arctic marginal seas, and the North Atlantic Ocean. Our data demonstrates support for the evolutionary consequences of oscillatory vicariance via transient oceanic isolation with subsequent secondary contact associated with fluctuating sea levels throughout the Quaternary period—which may serve as a model for the origins of Arctic marine fauna on a broad taxonomic scale.

Details

Title
Origins of the Greenland shark (Somniosus microcephalus): Impacts of ice-olation and introgression
Author
Walter, Ryan P 1   VIAFID ORCID Logo  ; Roy, Denis 2 ; Hussey, Nigel E 3 ; Stelbrink, Björn 4 ; Kovacs, Kit M 5 ; Lydersen, Christian 5 ; McMeans, Bailey C 6 ; Svavarsson, Jörundur 7 ; Kessel, Steven T 8 ; Porsmoguer, Sebastián Biton 9 ; Wildes, Sharon 10 ; Tribuzio, Cindy A 10 ; Campana, Steven E 7 ; Petersen, Stephen D 11 ; Grubbs, R Dean 12 ; Heath, Daniel D 13 ; Hedges, Kevin J 14 ; Fisk, Aaron T 13 

 Department of Biological Science, California State University, Fullerton, CA, USA; Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada 
 Department of Natural Resources and the Environment, Wildlife and Fisheries Conservation Center and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT, USA 
 Biological Sciences, University of Windsor, Windsor, ON, Canada 
 Justus Liebig University, Giessen, Germany 
 Fram Centre, Norwegian Polar Institute, Tromsø, Norway 
 Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada; Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada 
 Faculty of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland 
 Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, USA 
 Mediterranean Institute of Oceanography (MIO) UM 110, Aix-Marseille University, CNRS/INSU, Toulon University, IRD, Marseille, France 
10  Auke Bay Laboratories, AFSC/NMFS/NOAA/DOC, Ted Stevens Marine Research Institute, Juneau, AK, USA 
11  Conservation and Research Department, Assiniboine Park Zoo, Winnipeg, MB, Canada 
12  Coastal and Marine Laboratory, Florida State University, St. Teresa, FL, USA 
13  Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada 
14  Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB, Canada 
Pages
8113-8125
Section
ORIGINAL RESEARCH
Publication year
2017
Publication date
Oct 2017
Publisher
John Wiley & Sons, Inc.
e-ISSN
20457758
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1948310601
Copyright
© 2017. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.