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Dr. Brian Husband
Professor and Associate Dean (Academic)

 Dr. Brian Husband


Office: SSC 1469, 1477
Ext: 54790
Lab: SSC 1409/1410
Ext: 56014


My interest in plant population biology and evolution developed early in life through many hours of hiking and working in the Rocky Mountains of Canada. This led to a M.Sc. degree in which I investigated the biology of submerged aquatic plants and focused my interests on the ecology of small, isolated plant populations. For my Ph.D., I shifted my focus to the genetic and evolutionary aspects of small populations in a project on genetic drift and mating system variation in a South American aquatic plant. As a Postdoctoral Fellow, I continued this line of study, this time studying inbreeding and its negative consequences. Since coming to the University of Guelph, my research interests have diversified to include:

  1. the ecology and genetics of small populations,
  2. causes and consequences of genome duplication,
  3. function and evolution of plant reproductive systems; and
  4. ecological consequences of genetic diversity.

I am currently a member of the Canadian Society of Ecology and Evolution, Society for the Study of Evolution, American Association for Higher Education and the Canadian Botanical Association. I am a member of NSERC Grant Selection Committee 18 and the National Recovery Teams for Red Mulberry and American Chestnut.


B.Sc. - University of Alberta
M.Sc. - University of Alberta
Ph.D. - University of Toronto


My research and that of my lab group is focused on the ecology and genetics of plant populations. We study the mechanisms regulating genetic diversity and phenotypic evolution in plants, and, conversely, how evolutionary processes (drift, gene flow, adaptation, genetic diversity) affect the ecological function of populations (reproduction, growth, persistence, extinction). To understand these relationships we focus mainly on plant genetic systems, those reproductive attributes that govern mutation, gamete formation, pollination, fertilization, and organization of genetic diversity in populations.

Currently, my lab is involved in four related research areas:

I. Ecology and genetics of small populations

All populations contain a finite number of individuals, particularly those populations in restricted or marginal habitats.  This can have a profound effect on mating patterns and ecology, but the significance of population size for the evolutionary process is heavily debated. We have explored this issue through studies on effective population size, metapopulation dynamics, the effects of drift on mating system evolution, inbreeding depression, and the mechanisms by which hybridization causes extirpation of rare species.

II. Evolutionary significance of genome duplication.

Genome duplication above the diploid state (a.k.a. polyploidy) is widespread among plants and animals and is particularly common in flowering plants and ferns. Its prevalence in plants (and absence in many animals) has long puzzled biologists and recent mathematical models still argue that polyploidy should rarely evolve in sexual organisms with non-overlapping generations. Our research uses plant species with natural variation in ploidy (Chamerion, Galax, Malus) and mutagens that induce genome duplication to explore two major hypotheses: 1) genome duplication has a disproportionately large influence on rates of species diversification; 2) it enhances the adaptive potential and, hence, persistence of lineages that bear it.

III. Function and evolution of plant reproductive systems.

Plants exhibit a bewildering array of breeding systems, reflected by variation in gender, floral form and display, mechanisms of pollen transfer, and pathways of fertilization and seed maturation. Accounting for this sexual diversity is important because of its significance for population persistence, reproductive isolation and the organization of genetic diversity within and among populations. It also provides a useful focal point for studying the mechanisms of microevolution such as gene flow, genetic drift and selection. Our research currently focuses on two aspects of plant reproduction: the evolution of self-fertilization versus cross-fertilization (mating system), and the adaptive significance of dichogamy (temporal separation of male and female function). In both cases we are using comparative analyses, manipulative experiments and multi-generational selection studies to understand the evolution of these traits.

IV. Ecological impacts of hybridization and gene flow?

The importance of genetic diversity (mutation, gene flow, drift, heritability) to adaptive evolution is widely recognized, but it is less clear whether and how it affects ecological function and viability of populations. Understanding the ecological consequences of genetic diversity also have implications for conservation, restoration practices. Using a combination of genetic markers and manipulative studies, our research on hybridization between American and Eurasian chestnut (Castanea), Asian and native mulberry (Morus) and domestic and native apples (Malus) has allowed us to explore the conditions favouring gene exchange between species and the impacts on seed production and establishment. In addition, paternity analysis, flow cytometry and experimental crosses are being used to examine patterns of mating and the effects of mate diversity on reproductive success in domestic and native species.

V. Development and applications of plant barcoding

We are part of a national collaborative effort (comprising 4 labs) to develop barcoding tools for plants. The group has published one of the most extensive evaluations of potential barcode regions and has been instrumental (along with 3 other international groups) in facilitating an international agreement on a standard barcode region for land plants . Equally important we are advancing and exploring the applications of this tool for studies in ecology (belowground community structure and function) and evolutionary biology (phylogeography).

Selected Publications

Ecology and Genetics of Small Populations

McCracken, A., J.D. Bainard, M.C. Miller, and B.C. Husband. 2013. Pathways of introduction of the invasive aquatic plant Cabomba caroliniana. Ecology & Evolution 3:1427-1439 doi: 10.1002/ece3.530

Campbell, L.G. and B.C. Husband. 2007. Reproductive consequences of population size in self-incompatible plant, Hymenoxys herbacea (Asteraceae). New Phytologist 174:915-925.

Campbell, L.G. and B.C. Husband. 2005. Effective size and genetic drift in the clonal, self-incompatible plant Hymenoxys herbacea. Heredity 94:526-532.

Husband, B.C. and S.C.H. Barrett. 1998. Spatial and temporal variation in population size in Eichhornia paniculata in ephemeral habitats: implications for metapopulation dynamics. Journal of Ecology 86:1021-1031.

Barrett, S.C.H. and B.C. Husband. 1997. Ecology and genetics of ephemeral plant populations: Eichhornia paniculata (Pontederiaceae) in northeast Brazil. Journal of Heredity 88:277-284.

Genome Duplication

Husband, B.C. 2015. Effect of inbreeding on pollen tube growth and mutational load in diploid and tetraploid Chamerion angustifolium. in press, American Journal of Botany [Special Issue]

Kron, P. and B.C. Husband. 2015. Distinguishing 2N gamete nuclei from doublets in pollen using flow cytometry and pulse analysis. Cytometry A. Cytometry Part A 87A: 943-957. doi: 10.1002/cyto.a.22696

Thompson, K.A., B.C. Husband, H. Maherali. 2014. Climatic niche differences between diploid and tetraploid cytotypes of Chamerion angustifolium (Onagraceae). Am J. Bot. 101:1868-1875

Martin, S.L. and B.C. Husband. 2013. Adaptation of diploid and tetraploid Chamerion angustifolium to elevation but not local environment. Evolution 67: 1780-1791. DOI:10.1111/EVO.12065

Baldwin, S.J. and B.C. Husband 2013. The association between polyploidy and clonal reproduction in diploid and tetraploid Chamerion angustifolium. Molecular Ecology 22:1806-1819. doi:10.1111/mec.12217

Martin, S.L. and B.C. Husband. 2012 Whole genome duplication affects evolvability in natural populations of a flowering plant. PLos One. 7(9): e44784.doi:10.1371/journal.pone.0044784

Husband, B.C., S.J. Baldwin and J. Suda. 2012. The incidence of polyploidy in plants: major patterns and evolutionary processes. In, Plant Genomic Diversity Vol II, (J. Greilhuber, J. Dolezel, J.F. Wendel, Eds.) Springer

Martin, S.L. and B.C. Husband. 2009. The influence of phylogeny and ploidy on range size in North American angiosperms. Journal of Ecology 97: 913-922.

Maherali, H. A.F. Walden, B.C. Husband. 2009. Genome duplication and the evolution of physiological responses to water stress. New Phytologist, 184:721-731.

Husband, B.C., B. Ozimec, S. L. Martin and L. Pollock. 2008 Mating consequences of genome duplication: current patterns and insights from neopolyploids. International Journal of Plant Science, 169:195-206.

Ramsey, J., Robertson, A. and B.C. Husband 2007. Rapid adaptive divergence in new world Achillea, an autopolyploid complex of ecological races. Evolution 62:659-663.

Kron, P., J. Suda, and B.C. Husband. 2007. Applications of flow cytometry to evolutionary and population biology. Annu. Rev. Ecol. Evol. Syst. 38:847-876.

Soltis, D.E, P.S. Soltis, D.W. Schemske, J.F. Hancock, J.N. Thompson, B.C. Husband and W.S. Judd. 2007. Autopolyploidy in the angiosperms; have we grossly underestimated the number of species?. Taxon 56:13-30.

Yeung, K, A Savage, B.C. Husband, B. Igic, J. Miller, and J R. Kohn. 2005. Ploidy and gender in Lycium Californicum (Solanaceae). Evolution 59:2048-2055.

Suda, J., P. Kron, B.C. Husband and P. Trávnícek. 2006. Ploidy variation in evolutionary and systematic research on plants. In: Flow Cytometry of Plant Cells, Dolezel, J., J. Greilhuber and J. Suda (eds.).Wiley-VCH Verlag GmbH & Co., 438pp.

Kennedy, B., H. Sabara, D. Haydon and B.C. Husband. 2006. Pollinator-mediated assortative mating in mixed-ploidy populations of Chamerion angustifolium (Onagraceae). Oecologia, 150:398-408.

Husband, B.C. 2004. The role of triploids in the evolutionary dynamics of mixed-ploidy populations. Biological Journal of the Linnean Society 82:537-546.

Husband, B.C. and H.A. Sabara. 2004. Reproductive isolation between autotetraploids and their diploid progenitors in fireweed, Chamerion angustifolium. New Phytologist, 161:703-713.

Reproductive Systems

Miller, J.S., A. Kamath, B.C. Husband and R.A. Levin. 2015. Correlated polymorphism in cytotype and sexual system within a monophyletic species, Lycium californicum. Accepted, International Journal of Plant Science.

Kron P., Kwok A., and B.C. Husband. 2014. Flow cytometric analysis of pollen collected from individual bees provides information about pollen load composition and foraging behaviour. Ann. Bot. doi:10.1093/aob/mct257.

Ashman, T.-L., A. Kwok and B.C. Husband. 2013. Revisiting the dioecy-polyploidy association: alternate pathways and research opportunities. Cytogenetic and Genome Research 140: 241-255 (DOI: 10.1159/000353306).

Ozimec, B and B.C. Husband. 2011. Effect of recurrent selfing on inbreeding depression and mating system evolution in an autotetraploid plant. Evolution 65:2038-2049. doi:10.1111/j.1558-5646.2011.01259.x

Husband, B.C., B. Ozimec, S. L. Martin and L. Pollock. 2008 Mating consequences of genome duplication: current patterns and insights from neopolyploids. International Journal of Plant Science, 169:195-206.

Stehlik, I. P. Kron, S.C.H. Barrett and B.C. Husband 2007. Sexing pollen reveals female bias in a dioecious plant. New Phytologist 175: 185-194.

Clark, M.J. and B.C. Husband. 2007. Plasticity and flower closure in response to pollination in Chamerion angustifolium (Onagraceae). International Journal of Plant Science 168:619-625.

Routley, M.B. and B.C. Husband. 2006. Sexual interference within flowers of Chamerion angustifolium (Onagraceae). Evolutionary Ecology 20:331-334.

Routley, M.B. and B.C. Husband. 2005. Responses to selection on male-phase duration in Chamerion angustifolium (Onagraceae). Journal of Evolutionary Biology 18:1050-1059.

Routley, M and B.C. Husband. 2003. The effect of protandry on siring success in Chamerion angustifolium (Onagraceae) with different inflorescence sizes. Evolution 57:240-248.

Ecological Consequences of Genetic Diversity and Evolution

Kron and Husband. Botany. 2009. Hybridization and the reproductive pathways mediating gene flow between native Malus coronaria and domestic apple, Malus domestica. Botany 87: 864-874.

Burgess, K.S., M. Morgan, and B.C. Husband. 2008. Interspecific seed discounting and the fertility cost of hybridization in an endangered species. New Phytologist 177:276-284.

Burgess, K.S. and B.C. Husband. 2006. Habitat differentiation and the ecological cost of hybridization. Journal of Ecology 94:1061-1069.

Kron, P. and B.C. Husband. 2006. The effects of pollen diversity on plant reproduction: insights from apple. Plant Sexual Reproduction 19:125-131.

Burgess, K. S., M. Morgan, L. DeVerno and B. C. Husband 2005. Asymmetrical introgression between two Morus species (M. alba, M. rubra) that differ in abundance. Molecular Ecology 14: 3471-3483.

Burgess, K.S. and B.C. Husband. 2004. Maternal and paternal contributions to the fitness of hybrids between red and white mulberry (Morus, Moraceae). American Journal of Botany 91:1802-1808.

Husband, B.C. and L. G. Campbell. 2004. Demographic and genetic responses to new environments: implications for ex situ conservation. In Ex Situ Plant Conservation, E. Guerrant, K. Havens and M. Maunder, M. (eds.) Island Press, Washington.

Plant Barcoding

Percy D.M., G.W. Argus, Q.C. Cronk, A.J. Fazekas, P.R. Kesanakurti, K.S. Burgess, B.C. Husband, S.G. Newmaster, S.C.H. Barrett and S.W. Graham. 2014. Understanding the spectacular failure of DNA barcoding in willows (Salix): Does this result from a trans-specific selective sweep? Molecular Ecology 23:4737-4756.

Burgess, K.S., Fazekas A.J., Kesanakurti P.R., Graham S.W., Husband B.C., Newmaster S.G., Percy D.M., Hajibabaei M., Barrett S.C.H. 2011. Discriminating plant species in a local temperate flora using the rbcl + matK DNA barcode. Methods in Ecology and Evolution 2:333-340. doi: 10.1111/j.2041-210X.2011.00092.x

Kesanakurti, P.R., A.J. Fazekas, K.S. Burgess, D.M. Percy, S.G. Newmaster, S.W. Graham, S.C.H. Barrett, M. Hajibabaei, B.C. Husband. 2011. Spatial patterns of plant diversity below-ground as revealed by DNA barcoding. Mol. Ecol. 20:1289-1302.

CBOL Plant Working Group. 2009. Botanists Recommend a DNA Barcode for Land Plants. PNAS 106:12794-12797.

Aron J. Fazekas, Prasad R. Kesanakurti, Kevin S. Burgess, Diana M. Percy, Sean W. Graham, Spencer C. H. Barrett, Steven G. Newmaster, Mehrdad Hajibabaei, and Brian C. Husband. 2009. Are plant species inherently harder to discriminate than animal species using DNA barcoding markers? Molecular Ecology Resources 9: 130-139.

Aron J. Fazekas, Kevin S. Burgess, Prasad R. Kesanakurti, Sean W. Graham, Brian C. Husband, Steven G. Newmaster, Diana M. Percy, Mehrdad Hajibabaei, Spencer C. H. Barrett. 2008. Multiple multilocus DNA barcode combinations from the plastid genome discriminate plant species equally well. PLOS One: e2802.


As an instructor, my goal is to instil a love of discovery and learning at both undergraduate and graduate students. I have taught several undergraduate (Foundational Biology, Introductory Ecology, Plant Diversity and Evolution, Evolutionary Ecology) courses, ranging from first to fourth year, as well as a graduate course called Advances in Evolutionary Biology.

As Associate Dean Academic for the College of Biological Science, I am deeply invested in program development, curriculum reform, student support (awards, outreach, enrichment programs, student advising, early detection of risk) and instructor support through peer-consultation programs, summer research assistantships and teaching practice (Office of Educational Scholarship and Practice).

Husband BC, W.J. Bettger, C.L. Murrant, K Kirby, PA. Wright, S.G. Newmaster, J.F. Dawson, T.R. Gregory, RT. Mullen, A. Nejedly, G. van der Merwe, K. Yankulov, P. Wolf.. 2015. Applying a Linked-Course Model to Foster Inquiry & Integration in Large First Year Courses. Can. J. Higher Education 45: 244-260.

BIOL*1030/1040 Intro to Biology I & II
BIOL*4120 Evolutionary Ecology

Lab Personnel

Werdah Iqbal (MSc) - Co-advised by J. Colasanti (Dept. MCB)
Evan Pacey (PhD) - Co-advised by H. Maherali
Zackary Harris (MSc)
Wendy Van Drunen (PhD)
Adam Green (Post-doctoral Fellow)
Paul Kron (Research Associate)