Investigating how physiologies & genomes evolve

Montooth Lab







Cellular, physiological and behavioral adaptations to a variable environment 

The tremendous diversity in form and function across the Tree of Life is matched by an equally amazing diversity of cellular, physiological and behavioral adaptations that enable organisms to function in their environments. We investigate the genetic bases for plastic and fixed adaptive strategies, including how embryos defend themselves against thermal stress (Dr. Brent Lockwood), how mom’s preferences and her mRNAs might buffer this stress, how cellular plasticity evolves (Brandon Cooper,Katherine O'Brien, Omera Matoo) and how pathways and physiologies that mediate abiotic and biotic stress diverge among natural populations (Luke Hoekstra, Robert Kobey,Justin Buchanan).

Membranes, temperature and toxins

Organisms in nature do not experience single, isolated selection pressures. A remaining challenge is to describe phenotypic evolution as the integrated outcome of multiple selection pressures that may act differently across life stages.

We are investigating the cell membrane as an integrator of and responder to the combined effects of environmental ethanol and temperature. Ethanol disrupts cellular function by making membranes more fluid. In addition, because flies are ectotherms, their survival depends upon adjusting membrane fluidity in response to temperature. We are estimating selection gradients on basal and induced levels of biochemical and regulatory pathways that are predicted to mediate the impact of these ecologically relevant stresses on cellular function.

Modeling physiological performance as a function of biochemical flux

Physiology informs us about the biology that links genotypes and phenotypes. We are using equations of biochemical flux through pathways to develop modeling approaches that connect genetic to phenotypic variation.

Environmental ethanol and acetic acid present a toxin challenge to species that inhabit rotting fruit, but catabolism of these compounds yields a pool of acetyl-CoA to fuel metabolic processes. A model of biochemical flux through the three-step ethanol metabolic pathway reveals a ridge of high ethanol tolerance in the phenotypic landscape relating ADH and ACS activities to tolerance. Genotypes with high ADH activity can nonetheless have low tolerance when paired with low ACS activity, presumably due to accumulation of toxic intermediates. This suggests an interesting evolutionary dynamic that we are modeling and empirically testing, where the selective effects of genetic variants that enhance ADH activity depend upon the genetic background and activity of ACS. Similar approaches are being used to model variation in glycolytic pathways.

Representative Publications:

Cooper et al 2014 Functional Ecology
Hoekstra and Montooth 2013 BMC Evol Biol
Kobey and Montooth 2013 J Exp Biol
Cooper et al. 2012 Evolution
Montooth et al. 2006 J Exp Biol

Other Research:

mito-nuclear coevolution | energetics