esearch in my laboratory focuses on the population, evolutionary and conservation genetics of fishes and marine organisms. I am interested in how genetic variation is distributed within and among populations, how historical and ongoing processes have shaped the patterns of genetic variation that exist today, and what contemporary patterns of genetic variation can tell us about the history, ecology, evolutionary attributes and conservation status of populations.

Examples of past processes that influence contemporary genetic variation include previous ice ages that forced fishes into refugia where they evolved in isolation for periods of time, and much more recent human-related impacts that have drastically reduced the abundance of some species and populations.

Collecting guppies in Trinidad

Ongoing processes include environmental and biological factors that influence the extent to which organisms disperse or migrate from one area to another, and natural selection, which governs how organisms are adapted to particular environments. My students and I examine these factors and try to determine how they all mesh together by surveying genetic variation across populations using a variety of molecular techniques.

Recently, these techniques have begun to include next-generation DNA sequencing and ‘genomic’ analyses that are yielding far more data than was imaginable just a few years ago. One result is that we are learning much more about the pattern and extent of adaptive genetic variation in fish genomes.

My students and I also have broad interests in the use of molecular methods to answer questions about the ecology and reproductive biology of organisms. Studies in this category use microsatellites to investigate kinship among individuals within populations, and particularly, which individuals are the offspring of which other individuals.

I also serve as director of the Marine Gene Probe Laboratory, a multi-user laboratory situated in the Department of Biology and dedicated to the application of molecular genetic methods to a variety of biological sub-disciplines, including ecology, evolution, conservation and resource biology.

• Amanda Schweitzer - Phylogeography of Atlantic wolffish
• Sarah Saunders - Population genetics of striped bass
• Erin Chamberlain - Genetic variation in Lochaber Lake smelt
• Danielle Bourque - Pantophysin genes in fishes
• Megan Moriarty - Population genetics of Trinidadian guppies
• Lyndsey Baillie - Population genetics of Trinidadian guppies
  
  

  Shorthorn sculpin in Newfoundland

  
  

Graduate Students

• Craig Reynolds, MSc 2011. The effect of acidification on the survival of American eel (Anguilla rostrata).
• Dan Hasselman, PhD 2010. Influence of historical contingency and contemporary microevolutionary processes  on genetic structure of an anadromous fish.
• Megan McCusker, PhD 2009. The demographic history and population structure of three species of wolffishes across the North Atlantic Ocean.
• Ian Bradbury, PhD, 2007. Dispersal, homing, and connectivity in the estuarine fish, Osmerus mordax.
• Kim Murray, MSc 2005. Population genetic assessment of the endangered Atlantic Whitefish, Coregonus huntsmani, and the Lake Whitefish, C. Clupeaformis, in Atlantic Canada.
• Mark Coulson, PhD (in progress). Phylogeography, population structure and morphological adaptations among populations of anadromous rainbow smelt (Osmerus mordax).
• Adam Cook, PhD (in progress).  Genotypic variation and phenotypic expression of Nova Scotia coregonids.
• Craig Blackie, PhD (in progress). Contrasting historical and contemporary evolutionary processes in large lakes containing morphotypes of lake trout (Salvelinus namaycush) across North America.
• Jack Lighten, PhD (in progress). The application of Next-generation sequencing derived amplicons to the study of fish phylogeography
• Stanley King, PhD (in progress). The evolution of biodiversity in gyrodactylid parasites: characterizing genetic variation across spatial and temporal scales
• Lyndsey Baillie, MSc (in progress). Population structure and genetic response to the parasite Gyrodactylus in the Trinidadian guppy (Poecilia reticulata)
• Julie Rivard MSc (in progress) Ecological speciation of a landlocked population of rainbow smelt (Osmerus mordax) in Lochaber Lake, Nova Scotia
• Meghan McBride MSc (in progress) Defining the population structure and spatial distribution of the Alewife (Alosa pseudoharengus) in the Maritime Provinces and Maine

Beach seining juvenile smelt and striped bass for genetic analysis

Some Graduates' Occupations

• Research Scientist, Fisheries and Oceans Canada
• Biologist, Fisheries and Oceans Canada
• Research Scientist, United States Geological Service, Biological Resources Division, Anchorage, Alaska
• Research Scientist, National Marine Mammal Laboratory, Seattle.
• Research Scientist, National Marine Fisheries Service, Seattle
• Forensic Biologist, National Marine Fisheries Service, Seattle
• Post-doctoral Fellow, Canadian universities
• Laboratory Manager, Stanley Center for Psychiatric Research
  
  

  Migrating smelt in a Nova Scotia stream

Jensen, P.C. and P. Bentzen. 2012. A molecular dissection of the mating system of the Dungeness Crab, Metacarcinus magister (Brachyura: Cancridae). Journal of Crustacean Biology (in press).

Bradbury, I.R., M.W. Coulson, S.E. Campana, I.G. Paterson and P. Bentzen. 2011. Contemporary nuclear and mitochondrial DNA clines in a north temperate estuarine fish reflect Pleistocene vicariance. Marine Ecology Progress Series 438: 207–218.

Coulson, M.W., D. Denti, L. Van Guelpen, C. Miri, E. Kenchington and P. Bentzen. 2011. DNA barcoding of Canada’s skates. Molecular Ecology Resources doi: 10.1111/j.1755-0998.2011.03034.x

Schwartz, A.K., D. Weese, P. Bentzen, M.T. Kinnison, and A.P. Hendry. 2010. Dispersal, competition, and local adaptation all contribute to mating isolation in guppies. PLoS One 5(12):e15659. doi:10.1371/journal.pone.0015659

McCusker, M.R. and P. Bentzen. 2010. Historical influences dominate the population genetic structure of a sedentary marine fish, Atlantic wolffish (Anarhichas lupus), across the North Atlantic Ocean. Molecular Ecology 19(19):4228-4241.

Bradbury I.R, S. Hubert, B. Higgins, T. Borza, S. Bowman, I. Paterson, P.V.R. Snelgrove, C. Morris, R. Gregory, D.C. Hardie, J.A. Hutchings, D. Ruzzante, C. Taggart and P. Bentzen. 2010. Parallel adaptive evolution of Atlantic cod on both sides of the Atlantic Ocean in response to temperature. Proceedings of the Royal Society, Series B published online 30; June 2010 doi: 10.1098/rspb.2010.0985

McCusker, M.R. and P. Bentzen. 2010. Positive relationships between genetic diversity and abundance in fishes. Molecular Ecology doi: 10.1111/j.1365-294X.2010.04822.x.

Bradbury, I.R., M.W. Coulson, A. Cook and P. Bentzen. 2010. Evidence for divergence and adaptive isolation in post-glacially derived bimodal allopatric and sympatric rainbow smelt populations. Biological Journal of the Linnean Society. 101:583-594.

Dickerson, B.R., R.R. Ream, S.N. Vignieri and P. Bentzen. 2010. Population structure as revealed by mtDNA and microsatellites in northern fur seals, Callorhinus ursinus, throughout their range. PLoS ONE 5(5): e10671. doi:10.1371/journal.pone.001067.

McCusker, M.R. and P. Bentzen. 2010. Phylogeography of three North Atlantic wolffish species (Anarhichas spp.) with phylogenetic relationships within the family Anarhichadidae. Journal of Heredity doi: 10.1093/jhered/esq062

Willing, E.-M. P. Bentzen, M. Hoffmann, C. van Oosterhout, J. Cable, F. Breden, D.Weigel, C. Dreyer. 2010. Genome-wide single nucleotide polymorphisms reveal population history and adaptive divergence in wild guppies. Molecular Ecology 19:968-984.

Hasselman, D.J., R.G. Bradford and P. Bentzen. 2010. Taking stock: Defining populations of American shad (Alosa sapidissima) in Canada using neutral genetic markers. Canadian Journal of Fisheries and Aquatic Sciences. 67:1021-1039.

Bradbury, I.R., S.E. Campana and P. Bentzen. 2008. Estimating contemporary early life-history dispersal in an estuarine fish: integrating molecular and otolith elemental approaches. Molecular Ecology 17:1438-1450.

Bradbury, I.R. and P. Bentzen. 2007. Dispersal, life history, and non-linear genetic isolation by distance. Marine Ecology Progress Series 340:255-257.

Crispo, E. M.T. Kinnison, Paul Bentzen, D.N. Reznick, and A.P. Hendry. 2006. The relative influence of natural selection and geography on gene flow in guppies. Molecular Ecology 15(1):49-62.

Canino, M.F. and P. Bentzen. 2004. Evidence for positive selection at the pantophysin (Pan I) locus in walleye pollock, Theragra chalcogramma. Molecular Biology and Evolution 21(7):1391-1400.

Larson, S., R. Jameson, M. Etnier ‡, M. Fleming and P. Bentzen. 2002. Loss of genetic diversity in Sea Otters (Enhydra lutris) associated with the fur trade of the 18th and 19th centuries. Molecular Ecology. 11:1899-1904.

Bentzen, P., J.B. Olsen, J.E. McLean, T.R. Seamons and T.P. Quinn. 2001. Kinship analysis of Pacific salmon: insights into mating, homing, and timing of reproduction. Journal of Heredity 92:127-136.

Hendry, A.P., J.K. Wenburg, P. Bentzen, E.C. Volk, T.P. Quinn. 2000. Rapid evolution of reproductive isolation in the wild: evidence from introduced salmon. Science 290:516-518.

Shaklee, J.B. and P.  Bentzen. 1998.  Genetic identification of stocks of marine fish and shellfish.  Bulletin of Marine Science 62:589-621.

Bentzen, P., C.T. Taggart, D.E. Ruzzante, and D. Cook.  1996.  Microsatellite polymorphism and the population structure of Atlantic cod (Gadus morhua) in the northwest Atlantic. Can. J. Fish. Aquat. Sci. 53:2706-2721.

Wild guppies in a stream in Trinidad

• Bentzen Laboratory
• Marine Gene Probe Laboratory
• http://www.dal.ca/academics/programs/undergraduate/marinebio.html
(e-mail enabled browser is not required)