Download The ecological and genetic determinants of speciation

2017_38: The ecological and genetic determinants of
speciation
Supervisors: Professor Tim Barraclough ([email protected])
Department: Life Sciences
Why does life diversify into multiple species? Why do some taxa diversify into clearly
distinct species whereas others have blurred species boundaries? Does selection
favour complete speciation or porous species boundaries? Or are species instead an
incidental consequence of long-term isolation of populations?
Answering these questions requires knowledge of the rates and determinants of the
multiple steps by which speciation occurs. First, an existing species must encounter
conditions that favour divergence into separate species. Second, it must respond to
those conditions and evolve population differences and restrictions to gene flow. Third,
the descendant species must coexist and persist. Fourth, some of the descendant
species must encounter new conditions that favour further diversification, for example
by expanding their ranges.
We currently have good understanding of some parts (e.g. genetics of speciation,
diversity patterns), but poor knowledge of others – especially how ecological
conditions influence each step of diversification. Experiments that quantify key
processes over multiple generations have been lacking – much of our understanding
comes from observational evidence. In short, we lack the kind of robust theory and
evidence that is available for other ecological and evolutionary processes.
The goal of this PhD is to build synthetic understanding of speciation by assembling
information on the multiple steps in the process. The student will use several
approaches to tackle the problem including 2 or more of the following:
1) Mathematical or computational modelling, combining macroevolutionary and
population genetic approaches to model speciation dynamics
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet
Science and Solutions for a Changing Planet
2) Comparative population genetics to quantify the nature of species boundaries and
estimate the rates of different stages in speciation. An existing system that could be
adopted is the flowering plants of the Cape region of South Africa
3) ‘Speciation in action’ in the laboratory - using experimental evolution to determine
the conditions affecting selection on species boundaries. Existing systems that could
be adopted include wild yeasts or tree-hole bacteria.
4) Meta-analyses of published data from a range of animal, plant and/or microbial
groups, including the analysis of emerging whole genome data.
The balance of approaches will be flexible based on the student’s interests and would
be developed in discussion to address current gaps in understanding. If you have
strong interests in evolutionary biology and you are keen to develop theoretical,
molecular, experimental, field and/or molecular skills, then this is the PhD for you!
Motivation to develop your own ideas is more important than existing experience in
the above areas, which can be learned during the PhD.
For more information on topics and approaches currently used in the group, visit
barralab.ic.ac.uk or e-mail Tim Barraclough at [email protected].
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet