Troy Day

Title: Professor
Phone: 613-533-2431
Office: 409

Degrees and Honours

B.Sc. (University of British Columbia)

M.Sc. (University of British Columbia)

Ph.D. (Queen’s University)

Killam Postdoctoral Fellow (University of British Columbia)

Premier’s Research Excellence Award

Canada Research Chair in Mathematical Biology

Research Interests

My research falls under the broad heading of mathematical biology. More specifically, I use various mathematical and computational approaches to better understand evolutionary processes. I also have an integral empirical component to my research, aimed at testing theoretical predictions, and carried out in collaboration with faculty and students in the Department of Biology at Queen’s University.

My research interests in evolutionary biology began as an undergraduate student at the University of British Columbia, and I went on to complete a Master’s degree in Zoology at U.B.C., conducting experiments on the evolution of phenotypic plasticity in the small freshwater fish, Gasterosteus aculeatus (the threespine stickleback). During this time I became increasingly interested in theoretical evolutionary biology and, as a result, I went to Queen’s University where I completed a PhD in mathematical biology. In my doctoral dissertation I developed some general mathematical results for constructing certain types of models of kin selection. My dissertation also applied these techniques to several different areas of evolutionary biology, including life history evolution and evolutionary medicine.

Currently, research in my lab is concentrated in three main areas: (i) evolutionary medicine, (ii) the evolution of genomic conflict/imprinting, sexual conflict, and sexual selection, and (iii) the effects of spatial population structure on evolutionary change.

1. Evolutionary Medicine – My research in evolutionary medicine has focused largely on two topics: the evolution of parasite virulence, and the evolution of senescence.

Evolutionary theory is challenging the deeply entrenched notion that successful pathogens eventually evolve toward benign coexistence with their hosts. Emerging theory and experimental data have revealed that the degree of evolved virulence (defined as parasite-induced host mortality) depends on the ecology of both host and parasite. The challenge for theoreticians and empiricists is to discover the specific factors that direct virulence evolution. There are a number of theoretical projects that my lab is carrying out to address this question, using a variety of modeling approaches from evolutionary biology and mathematical epidemiology. I am also planning some experimental tests of this theory, in collaboration with researchers in the Department of Biology.

Senescence is the deterioration in reproductive potential of an organism as it ages. There are two main hypotheses for the evolution of senescence, the mutation accumulation (MA) hypothesis, and the antagonistic pleiotropy (AP) hypothesis. Research in my lab is examining a number of extensions of these hypotheses, as well as potential synergistic interactions that occur when both processes are operating simultaneously. Most of this research is being carried out using a combination of mathematical analysis and computer simulation. The results will hopefully provide new suggestions about how these two hypotheses might be distinguished experimentally.

2. Evolutionary Conflicts and Sexual Selection – Recent theory has changed the way in which biologists view interactions among biological entities by illustrating the importance of evolutionary conflicts at various levels of biological organization. My lab’s overall research objectives in this area are to develop a consistent and general theoretical framework for understanding and predicting the outcome of these conflicts. This research falls into two broad areas: sexual conflict/sexual selection and genomic conflict and imprinting.

Both males and females of many species have evolved surprisingly intricate characteristics that appear to be involved in sexual interactions between the two. Much of the current thinking about how such traits evolve is based on the premise that there is an evolutionary conflict of interest between the two parties over many aspects of mating and reproduction. Over the last few years several papers have been published that contain data bearing on these issues, but as yet there is still no complete quantitative theoretical framework in which to interpret these results. Consequently, there are conflicting opinions about what we should expect to observe under different evolutionary scenarios. My lab is developing theory to unify these experimental findings and to generate new predictions that can be tested.

One of the most intriguing types of evolutionary conflict documented occurs at the genome level. It need not be the case that different loci within a genome, or even different alleles at the same locus within a genome be acted upon in the same way by natural selection. For example, there is now good empirical evidence and theory suggesting that natural selection acts differently on alleles depending upon their ‘parent of origin’. In some cases this conflict appears to have resulted in the evolution of differential allelic expression depending upon whether the allele was inherited maternally or paternally. This is believed to occur through genomic imprinting. Currently my lab is developing theory to better understand the relationship between genomic imprinting and sexual conflict, as well as to explore the possibility that genomic imprinting might play an important role in the evolution of secondary sexual characters.

3. Effects of Spatial Population Structure – It has long been known that limited movement of organisms (population viscosity) can result in the genetic structuring of populations, and this can have important evolutionary consequences. I am interested in using theory and modeling to explore the evolution of resource exploitation strategies, life history characters, virulence, and speciation in such spatial contexts. I am also planning some empirical tests of this theory, in collaboration with researchers in the Department of Biology.

Contact Info

Department of Math & Stats
Jeffery Hall, 48 University Ave.
Kingston, ON Canada, K7L 3N6
Phone: (613) 533-2390
Fax: (613) 533-2964
Office Hours: 8:30am-12:00pm & 1:00pm-4:30pm