MBF Seminar Series
KUSHLAN CHAIR CANDIDATE
Kevin G.
McCracken
University of Alaska, Fairbanks
Genetic
Adaptation & Phenotypic Plasticity in
South American Waterbirds
My research interests are in evolutionary biology and
the genetics of adaptation. Field studies and
analytical methods from a variety of different
disciplines including genetics, physiology, protein
chemistry, and wildlife population biology are being
used to address questions about the process of
adaptation and natural selection, at both the
molecular level and in whole organisms. Conservation
of waterfowl and other waterbird species inhabiting
high-altitude regions such as the Andes are of
particular interest.
High-altitude regions are characterized by extreme
differences in ambient pressure and temperature that
vary across elevational gradients. Hypoxia in
particular is one of the most important factors
influencing survival at high elevations, and
biochemical changes in the blood protein hemoglobin
(Hb) have been shown to mitigate the effects of
chronic hypoxia in high-altitude adapted populations.
Surveys of hemoglobin amino acid polymorphism in
Andean waterfowl suggest that genotypic variants that
are over-represented in high-altitude populations have
different fitness rankings in different elevational
zones and influence Hb-O2 affinity. Our studies have
further revealed that parallel substitutions evolved
in distantly related lineages and are concentrated in
the same few regions of the protein. Experimental
studies of Hb function and blood properties are being
combined with genome-wide population genetics analyses
to study the mechanistic basis of these apparent
adaptations. One question we aim to answer is whether
the same or different molecular mechanisms underlie
parallel changes in replicate lineages that
independently colonized the Andes and other
high-altitude regions. Other questions focus on the
role of phenotypic plasticity and how it may
alternatively promote the process of genetic
adaptation or shield genotypes from natural selection.
Specifically, we are examining how individuals
modulate their Hb-O2 carrying capacity and vary their
ventilation rate and cardiovascular response when they
disperse across elevational gradients or are
challenged with acute hypoxia.
TUESDAY, FEBRUARY 12, 2013
12noon
RSMAS
campus, S/A 103
