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Genetic variation in the neritic squid Loligo forbesi (Myopsida: Loliginidae) in the northeast Atlantic Ocean

Genetic variation in the neritic squid Loligo forbesi (Myopsida: Loliginidae) in the northeast... 227 122 122 1 1 A. S. Brierley J. P. Thorpe G. J. Pierce M. R. Clarke P. R. Boyle Department of Environmental and Evolutionary Biology University of Liverpool, Port Erin Marine Laboratory TM9 6JA Port Erin Isle of Man Department of Zoology University of Aberdeen Tillydrone Avenue AB9 2TN Aberdeen Scotland British Antarctic Survey High Cross, Madingley Roach CB3 OET Cambridge England Abstract Horizontal starch gel electrophoresis was employed to investigate levels of genetic differentiation between 13 samples of the neritic squid species Loligo forbesi Steenstrup obtained from throughout the majority of its known geographical range. Six enzyme loci identified in a preliminary study as being polymorphic were screened for variation between samples. No significant differences in allele distribution were detected between any of the samples obtained from the Faroe Bank in the north to Lisbon in the south, suggesting that squid throughout this range in the vicinity of the continental shelf are able to maintain panmixia, and effectively belong to a single population sharing a common gene pool. No clinal variation in allele distribution was detected throughout this range, a result which complements the findings of a detailed morphological companion study of the same individuals. Comparison of this homogenous European continental shelf population with squid from the Azores revealed highly significant ( P <0.01) differences in allele distribution at five of the six polymorphic enzyme loci studied. A genetic identity value ( I ) equivalent to 0.93 over 33 loci was obtained. Analysis of F -statistics suggested migration rates between sites to be as low as one individual per five generations, a rate deemed insufficient under most models to prevent divergence by random genetic drift. The large distance and oceanic depths separating the Azores from continental Europe seem to present an effective barrier to gene flow to L. forbesi , a squid belonging to a family considered to be confined in distribution to relatively shallow, near coastal waters. The two populations of squid in the Azores and along the European continental shelf currently both ascribed to L. forbesi should therefore probably best be regarded as relative subspecies. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Marine Biology Springer Journals

Genetic variation in the neritic squid Loligo forbesi (Myopsida: Loliginidae) in the northeast Atlantic Ocean

Brierley, A.; Thorpe, J.; Pierce, G.; Clarke, M.; Boyle, P.
Marine Biology , Volume 122 (1) – Mar 1, 1995
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References (40)

Publisher
Springer Journals
Copyright
Copyright © 1995 by Springer-Verlag
Subject
Life Sciences; Biomedicine general; Oceanography; Ecology; Microbiology; Zoology
ISSN
0025-3162
eISSN
1432-1793
DOI
10.1007/BF00349280
Publisher site
See Article on Publisher Site

Abstract

227 122 122 1 1 A. S. Brierley J. P. Thorpe G. J. Pierce M. R. Clarke P. R. Boyle Department of Environmental and Evolutionary Biology University of Liverpool, Port Erin Marine Laboratory TM9 6JA Port Erin Isle of Man Department of Zoology University of Aberdeen Tillydrone Avenue AB9 2TN Aberdeen Scotland British Antarctic Survey High Cross, Madingley Roach CB3 OET Cambridge England Abstract Horizontal starch gel electrophoresis was employed to investigate levels of genetic differentiation between 13 samples of the neritic squid species Loligo forbesi Steenstrup obtained from throughout the majority of its known geographical range. Six enzyme loci identified in a preliminary study as being polymorphic were screened for variation between samples. No significant differences in allele distribution were detected between any of the samples obtained from the Faroe Bank in the north to Lisbon in the south, suggesting that squid throughout this range in the vicinity of the continental shelf are able to maintain panmixia, and effectively belong to a single population sharing a common gene pool. No clinal variation in allele distribution was detected throughout this range, a result which complements the findings of a detailed morphological companion study of the same individuals. Comparison of this homogenous European continental shelf population with squid from the Azores revealed highly significant ( P <0.01) differences in allele distribution at five of the six polymorphic enzyme loci studied. A genetic identity value ( I ) equivalent to 0.93 over 33 loci was obtained. Analysis of F -statistics suggested migration rates between sites to be as low as one individual per five generations, a rate deemed insufficient under most models to prevent divergence by random genetic drift. The large distance and oceanic depths separating the Azores from continental Europe seem to present an effective barrier to gene flow to L. forbesi , a squid belonging to a family considered to be confined in distribution to relatively shallow, near coastal waters. The two populations of squid in the Azores and along the European continental shelf currently both ascribed to L. forbesi should therefore probably best be regarded as relative subspecies.

Journal

Marine Biology – Springer Journals

Published: Mar 1, 1995

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