Dr. Brian Husband
Professor
Canada Research Chair, Tier 2

Dr. Brian Husband

Email: bhusband@uoguelph.ca

Office: SCIE 1469
Ext: 54790
Lab: SCIE 1409/1410
Ext: 56014

Profile

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.

Education

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

Research

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.

Selected Publications

Ecology and Genetics of Small Populations

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

Suda, J., P. Kron, B.C. Husband and P. Trávnícek. 2006. Ploidy variation in evolutionary and systematic research on plants. In:  Plant Flow Cytometry. Accepted.

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.

Husband, B.C. and H.A. Sabara. 2003. Reproductive isolation between autotetraploids and their diploid progenitors in fireweed, Chamerion angustifolium. New Phytologist: online publication date December 18, 2003 (http://www.blackwell-synergy.com/links/toc/nph/161/1). Print citation: New Phytologist: 161:703-713.

Reproductive Systems

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.

Wolfe, B., B.C. Husband, and J.N. Klironomos. 2005. Effects of a belowground mutualism on an aboveground mutualism. Ecology Letters 8:218-223.

Routley, M.B., R.I. Bertin and B.C. Husband. 2004. Correlated evolution of dichogamy and self-incompatibility: a phylogenetic perspective. International Journal of Plant Science 165:983-993.

Effects of genetic diversity and evolution on population function and persistence

Kron, P. and B.C. Husband. 2006. The effects of pollen diversity on plant reproduction: insights from apple. Plant Sexual Reproduction, DOI: 10.1007/s00497-006-0028-2

Burgess, K.S. and B.C. Husband. 2006. Habitat differentiation and the ecological cost of hybridization: effects of introduced mulberry (M. alba) on native red mulberry (M. rubra). Journal of Ecology, doi:10.1111/j.1365-2745.2006.01152.x

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.

Teaching

As a teacher, my goal is to instill a love of scientific discovery and learning at both the undergraduate and graduate level. I teach several undergraduate courses (Introductory Biology [BIOL*103-104] as well as Evolutionary Ecology [BIOL*4120]) and its graduate version. In each course my approach is to involve students in the process of scientific investigation rather than just the terms and facts that are produced. This means hands-on experience, critical thinking, library research and discussions about scientific controversies and the personalities involved. By involving students in all aspects of the process of scientific discovery, I hope to nurture both intellectual growth and an appreciation for plants.

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

Grad Students

Martin, Sara (PhD)
McCracken, Andree (MSc)
Sabara, Holly (PhD)
Roy, Yvette (MSc)
Baldwin, Sarah (MSc)