Eckert Lab - Plant Evolution and Population Genetics

Plant Ecology & Evolution
Dr. Christopher G. Eckert, Department of Biology, Queen's University, Kingston, Ontario K7L 3N6 Canada
Phone +1-613-533-6158, Fax +1-613-533-6617, chris.eckert[at]queensu.ca

The research in my lab investigates two major evolutionary trends in flowering plants: the evolution of self-fertilization and the evolution of asexuality. We also have a strong interest in the genetic & ecological consequences of colonization as well as the evolution of geographical range limits. These interests dovetail with conservation research on invasive and endangered species.

We use a combination of large-scale geographical populations surveys, manipulative experiments in natural populations, DNA and protein marker-gene analysis of reproductive patterns & genetic structure, plus a variety of lab-based tools, including quantitative genetics, developmental analyses, image analysis, and computer modeling.

Our field work takes place in a variety of locations across North America and Europe. Currently, we have projects on the coevolution of geographic range limits and the mating system based on the pacific coast of North America, a large-scale analysis of adaptive evolution during biological invasion based in Europe and eastern North America, and a phylogeographic study of plants that occur as disjunct populations on critically-imperiled Alvar habitat in the Great Lakes region.

Evolution of Self-Fertilization in Flowering Plants
The transition from an outcrossing mating system to one involving predominant self-fertilization is one of the most common evolutionary trends in flowering plants, and a large proportion of species exhibit mating systems that combine selfing and outcrossing. Moreover the degree of selfing vs outcrossing can greatly influence the genetic structure of populations, their evolutionary potential and their ecological and demographic properties. Mathematical models propose that the evolution of selfing depends on a suite of genetic and ecological selective forces. We are testing these models using manipulative experiments conducted in natural populations in conjunction with marker-gene analysis of mating patterns and quantitative genetics. In particular, we are studying this problem by examining how and when selfing occurs as well as the important consequences of different modes of self-fertilization such as reproductive assurance, seed discounting and pollen discounting.

Evolution of Geographical Range Limits
Every species has a limited geographical range and there is tremendous variation, even among closely related species, in the size and position of the range. Over the short term, a species' range limit is set by a combination of abiotic factors and biotic factors that jointly affect population demography or metapopulation dynamics. From an evolutionary perspective, however, the fact that species ranges are limited over the long term poses a major problem: why doesn't natural selection cause populations at the range margin to adapt to their local conditions and spread outward? This directly questions the limits of adaptive evolution. Recent theory proposes that ranges are limited because populations become increasing small, less productive and more sparsely distributed towards the margins of the range such that local adaptation at the range limit is thwarted by gene flow (m) from larger, more productive central populations .Plants pose a particular challenge for migration-selection models of range limits. Most have multifaceted reproductive strategies that combine sexual reproduction with clonal reproduction and inbreeding with outbreeding. And, reproductive mode can change drastically near the range limit and greatly affect population genetic diversity and gene flow in marginal populations. These reproductive shifts might shape the evolution of range limits by themselves or by interacting with other evolutionary forces.

Evolutionary Consequences of Biological Invasion
Colonization, especially when it involves the movement of a species from one part of the world to another, can have a variety of ecological and genetic consequences, which, in turn may greatly affect the evolution of reproductive and life-history strategies. Understanding the consequences of colonization is also central to the effective management of invading species. We are investigating the ecological and genetic consequences of colonization by comparing native and introduced populations of purple loosestrife and flowering rush .

Evolution of Asexuality in Flowering Plants
Most flowering plants combine sexual reproduction with some form of asexual reproduction, yet the selective consequences of the two reproductive modes as well as the ecological and genetic factors controlling the balance between them are poorly understood. We are investigating the causes and consequences of the two major modes of asexual reproduction: vegetative propagation and apomixis.

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	Evolution of Self-Fertilization in Flowering Plants The transition from an outcrossing mating system to one involving predominant self-fertilization is one of the most common evolutionary trends in flowering plants, and a large proportion of species exhibit mating systems that combine selfing and outcrossing. Moreover the degree of selfing vs outcrossing can greatly influence the genetic structure of populations, their evolutionary potential and their ecological and demographic properties. Mathematical models propose that the evolution of selfing depends on a suite of genetic and ecological selective forces. We are testing these models using manipulative experiments conducted in natural populations in conjunction with marker-gene analysis of mating patterns and quantitative genetics. In particular, we are studying this problem by examining how and when selfing occurs as well as the important consequences of different modes of self-fertilization such as reproductive assurance, seed discounting and pollen discounting.
	Evolution of Geographical Range Limits Every species has a limited geographical range and there is tremendous variation, even among closely related species, in the size and position of the range. Over the short term, a species' range limit is set by a combination of abiotic factors and biotic factors that jointly affect population demography or metapopulation dynamics. From an evolutionary perspective, however, the fact that species ranges are limited over the long term poses a major problem: why doesn't natural selection cause populations at the range margin to adapt to their local conditions and spread outward? This directly questions the limits of adaptive evolution. Recent theory proposes that ranges are limited because populations become increasing small, less productive and more sparsely distributed towards the margins of the range such that local adaptation at the range limit is thwarted by gene flow (m) from larger, more productive central populations .Plants pose a particular challenge for migration-selection models of range limits. Most have multifaceted reproductive strategies that combine sexual reproduction with clonal reproduction and inbreeding with outbreeding. And, reproductive mode can change drastically near the range limit and greatly affect population genetic diversity and gene flow in marginal populations. These reproductive shifts might shape the evolution of range limits by themselves or by interacting with other evolutionary forces.
	Evolutionary Consequences of Biological Invasion Colonization, especially when it involves the movement of a species from one part of the world to another, can have a variety of ecological and genetic consequences, which, in turn may greatly affect the evolution of reproductive and life-history strategies. Understanding the consequences of colonization is also central to the effective management of invading species. We are investigating the ecological and genetic consequences of colonization by comparing native and introduced populations of purple loosestrife and flowering rush .
	Evolution of Asexuality in Flowering Plants Most flowering plants combine sexual reproduction with some form of asexual reproduction, yet the selective consequences of the two reproductive modes as well as the ecological and genetic factors controlling the balance between them are poorly understood. We are investigating the causes and consequences of the two major modes of asexual reproduction: vegetative propagation and apomixis.