Research projects
Our goal is to understand how and why specific phenotypes
arise
during evolution. We use all the available approaches (genomics,
developmental biology, biochemistry, behavioral assays, genetics,
etc.)
to tackle the problem.
http://www.biology.ed.ac.uk/research/groups/jdeacon/
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Drosophila pachea
is one of the rare insect species that is unable to
metabolise
cholesterol. It lives exclusively on one host plant, the
senita cactus,
and it requires 7-dehydrogenated sterols produced by this
cactus to
survive. We identified several coding
mutations in an enzyme gene that
have made D. pachea
dependent
on its host cactus. Our work suggests that these mutations
are
beneficial for D.
pachea and
have been subject to positive selection.
Drosophila
pachea has
also evolved a resistance towards the toxic compounds of
its host
cactus. We would like to investigate the genetic basis of
this
resistance.
We also plan to study how a moth species adapted
to the senita cactus.
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How left-right asymmetries in organ size
develop remains a mystery. Drosophila
pachea has evolved a unique left-right asymmetry
in genitalia
lobes. No left-right size asymmetry has been described in
D. melanogaster.
We are trying to
uncover the mechanisms that triger asymmetric lobe
development
and the role of these asymmetric lobes during copulation.
We use a
stock of Drosophila
pachea
containing spontaneous symmetric mutant males and we
perform micro-scale laser removal of lobe bristles and
micro-scale surgery of lobes. We are also examining
left-right asymmetries in behavior and morphology in
species closely related to D.
pachea, in order to understand how left-right
asymmetry in lobe size evolved in D.
pachea.
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How robust phenotypes evolve despite
developmental noise remains unclear. Does
evolution of a new phenotype
goes through an intermediate unstable state that
is then stabilized due
to fixation of additional mutations? Or does it
evolve directly as a
new phenotype that is stable across various
external conditions? We are
examining the evolution of a new genital sensory
organ pattern in Drosophila
santomea and aim to
better characterize the molecular mechanisms that
stabilize this
recently evolved phenotype. Our goal is
three-fold: (1) characterize
and compare the development of these structures in
D. santomea and
its
closely-related species, (2) identify the
underlying genes and
mutations that act collectively to produce a
robust phenotype in pure
species, and (3) unveil the selective forces at
play on this evolved
phenotype.
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We wish to understand how diverse biological
forms develop and evolve. To try to understand how genes
and cellular
mechanisms modulate organ shape in a subtle and precise
way, we are
examining the precise changes in genitalia lobe shape that
have
appeared during evolution in Drosophila
melanogaster and its three closely related
species. We would
like to identify genes and mutations responsible for
specific changes
in lobe shape and to characterize in detail the
development of the
posterior lobe at the cellular level in D.
melanogaster, in its closely
related species, and in hybrid lines that carry a small
piece of
another species genome.
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