Mathemati cs / Bi ology / Computer Sci ence
Understanding Complex Systems
Mathematical biologist
Leah Keshet is one of a
growing number of
interdisciplinary
researchers who use
mathematical modelling
to help solve some of
science’s most puzzling
questions.
MITACS team leader, Mathematics Professor
Leah Keshet holds a model of an actin
filament network.
WHAT KEEPS A SCHOOL OF FISH OR A SWARM OF BEES
together? What forms or breaks up a string of
molecules? What controls the shape and movement of a cell? Why do nerve cells degenerate and die
in diseases such as Alzheimer’s and ALS. The common link in these questions is that they all involve
highly complex systems. Leah Keshet uses mathematical tools such as differential equations and
computer modelling rather than in vitro experiments to try to answer them. Keshet says her binary
love for both math and biology is inherited. "My mother was a biologist and my father is a mathematician.
I was fascinated with both areas and eventually wound up in the middle."
Her initial research involved modelling the way that actin filaments—components of the cytoskeleton or the structural scafMITACS—Using Mathematics
folding of cells—interact to form different kinds of structures,
to Fight Disease
such as bundles, loose networks, or gels, and what role this plays
An exciting development for Leah
in disease. In cancerous cells, the actin cytoskeleton is one of the
Keshet
and her math-bio colleagues
cellular components that can be severely affected, resulting in the
Robert
Miura
and Yx Li was the announceabnormal motion of these cells. In cystic fibrosis, cells spill out very
ment
of
major
funding by the federal govlong actin filaments that produce a heavy mucus
ernment for The Mathematics of Informain the lungs. "Polymer chemistry has traditionally
tion Technology and Complex Systems
been dominated by physical chemistry and ther(MITACS), a new Network Centres of
modynamic techniques." Keshet notes. "I look at
Excellence (NCE). This initiative, of more
these problems from a kinetic and differential
than $14.5 million over four years, will bring
equations perspective."
together 175 researchers at 22 Canadian
Keshet’s research is not confined to the microuniversities to develop new mathematical
scopic aspect of biology. She and associates Alex
tools for Canadian industry. Keshet heads
one of the biomedical MITACS teams.
Mogliner and Danny Grunbaum have also been
In one of the recently funded MITACS
looking at a much larger picture—the complexprojects,
Keshet is studying signal transity of swarming behaviour in animals and insects.
duction, the process of conThey use mathematical models to shed light
verting hormonal signals to
on what keeps a swarm
Insuli n
cellular response which
e
n
mbra
or flock together,
Cell me
involves a complex bior
rec epto
what governs its
Insuli n
chemical cascade. Leah
shape, and why it
Keshet is trying to detercan travel for long
mine what happens when
distances without
this complex interaction
losing individuals.
goes awry. She is workThis research has
ing with Kinetek, a Vanin
couver-based pharmaimplications for
te
ro
gp
Doc k in
ceutical company, to model the
behavioural ecology,
eshet
: Leah K
architecture of these cascades in order to
Diagram
conservation of natural
analyze the effects of hormonal signals
resources such as fish, management strategies
and try to understand their role in diseases
for bee farming, and pest control.
such as diabetes and cancer.
In addition to her research and teaching,
Another MITACS project is her work
Keshet is actively involved in curriculum develwith associate Chris Shaw, student Magopment. She is helping to develop calculus courses
dalena Luca, and post-doctoral fellow
for life sciences students, and she is one of the creators of CalcuAlexandra Chavez-Ross on neurodegenerlus OnLine. Keshet also designed and co-taught courses in Sciative diseases such as Alzheimer’s and
ence One, UBC’s innovative multi-disciplinary program for first-year
ALS. In collaboration with industry partner
science students.
In Silico (Boston), they are trying to discover how microglia (the brain’s "immune
When not teaching, developing courses or solving complex
cells") affect the balance between healthy
mathematical problems, Keshet says she enjoys spending time with
and stressed neurons, and how excitotoxher two young sons. "They both have wonderful energy and ideas."
ins (molecules that mimic some neuroThis obviously influences her approach to life and work—intertransmitters) cause neural stress and
active, curious, and open to possibilities.
degeneration.
i ssue
5.1
dec ember
1999
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