Research
We are Eco-Evo-Devo... |
We are in the midst of a conceptual revolution in the biological sciences as the traditional borders between the fields of ecology, molecular, developmental, and evolutionary biology are breaking down. The general goal of research in the Abouheif lab is to integrate these fields to understand how genes and environment interact during development to generate phenotypic diversity.
One of the most important discoveries in developmental biology is that a relatively small number of regulatory genes that play critical roles during development, such as the Hox genes, are highly conserved across the animal kingdom. To understand how these genes interact with their environment to generate diversity we study them in the context of phenotypic plasticity – a universal feature of all living organisms. We focus on a particularly striking form of phenotypic plasticity called polyphenism, which is the ability of a single genome to produce two or more discrete phenotypes within a population in response to environmental cues:
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Polyphenism is an ecologically important trait that helps organisms adapt to variable environments, and is a wide spread trait occurring in many plants and animals.
We primarily focus on caste polyphenism in ants. Ants are one of the most ecologically dominant and evolutionarily successful organisms on our planet. A key to this amazing success is their ability to cooperate and form organized societies. Like honeybees, their social organization is built on the division of labor between different ‘castes’ within a colony. Almost all ant species possess at least two castes – queens and workers:
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The differences between queens and workers can be dramatic – queens possess fully functional wings, are reproductively active, and can live up to 30 years, while workers are wingless, reproduce rarely, and live for just a few months. These dramatic differences arise as a consequence of environmentally induced differences in gene expression during queen and worker development. |
Therefore, a major goal in the Abouheif lab is to characterize the gene networks that underlie queen and worker caste development in ants. In doing so we will reveal how ecological and social environments can influence the development and evolution of these gene networks, and how the changes in these gene networks can feedback to affect the social organization and ecological environments of ants.
The gene network underlying wing polyphenism in ants is a good example (see panel 1, figure below). Queens and males develop fully functional wings to fly up in the air to mate and disperse, but workers do not. The gene network that controls wing development in Drosophila and other holometabolous insects is conserved in the winged queens and males of the ant Pheidole morrisi (green boxes, panel 2). In contrast, in the wingless soldiers (panel 3) and workers (panel 4), the expression of specific genes is interrupted as indicated by the red boxes). Therefore, interruptions can be identified and can evolve between different worker castes within a species (compare red boxes between soldiers/panel 3 to workers/panel 4) as well as between the workers castes of different ant species (see Abouheif & Wray, 2002).
Pheidole morrisi |
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wing patterning network (panel 1) |
queen (panel 2) |
soldier (panel 3) |
worker (panel 4) |
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If we can understand why these gene networks have evolved between different castes and species, we will learn something fundamental about how genes interact with their environment during development, and how changes in this interaction can lead to phenotypic diversity.
Collaborations:
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Developmental and adaptive basis of appendage evolution in water striders This work was initiated in collaboration with Dr. Locke Rowe (Tier I CRC and Department Chair) at the University of Toronto. Water striders are semi-aquatic bugs, which are adapted for locomotion on the water surface. In our first study published in PLoS Genetics (Khila et al. 2009), we discovered that the Hox gene, Ultrabithorax, facilates their locomotion by functioning to elongate the mid-legs but shorten the hind legs. This is a surprising discovery because Ultrabithorax performs opposite functions in two adjacent segments of the body. We are now following up this study to trace how the opposite functions of Ubx evolved in semi-aquatic bugs. Water striders are also model systems to understand the ecology and evolution of sexual conflict between males and females. We are now trying to understand the developmental and genetic basis of traits that have evolved in response to sexual selection and conflict. |
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Funding Agencies
The Abouheif Lab would like to graciously thank the following funding agencies for providing financial support for this research:
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Fonds de recherche sur la nature et les technologies |
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Natural Sciences and Engineering Research Council |
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Canadian Foundation for Innovation |
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Canada Research Chairs |
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National Science Foundation |
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Alfred P. Sloan Foundation |
Scientific Societies and Journals supporting EvoDevo
- Society of Integrative and Comparative Biology
- Canadian Society of Zoologists, Comparative morphology and development section
- EvoDevo.org
- Canadian Society of Ecology and Evolution
