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alan pepper out in a field with plants to collect

Alan Pepper
Department of Biology, TAMU

Title: “Between a rock and a hard place: Evolutionary adaptation to an extreme terrestrial environment”


Evolutionary adaptation to environment is a fundamental attribute of all living things. Because plants are sessile (immobile), they cannot seek out a new environment in the face of challenging conditions, and thus make excellent organisms for both laboratory and field studies of environmental adaption. The focus of my lab is the study of the genetic mechanisms of plant adaptation to ultramafic or ‘serpentine’ geological outcrops. Derived from highly unusual surface exposures of the Earth’s mantle, serpentine outcrops are globally rare, and are characterized by high levels of toxic heavy metals such as nickel, chromium and cobalt. They also have very low levels of essential mineral nutrients including nitrogen, phosphorous, potassium, calcium and sulfur. The resulting ‘serpentine barrens’ also have low levels of organic matter and are prone to drought. Only a very few plants have evolved to thrive in these conditions. In this seminar I will a describe a highly- tractable model system built from two ecologically contrasting populations of the rare annual plant Caulanthus amplexicaulis (Brassicaceae). Using an array of genetic and genomic approaches, this model has led to advances in our understanding of adaptation to the complex and harsh serpentine environment. A fundamental question of our work is that of how organisms simultaneously adapt to multiple serious environmental challenges. In this regard, our presentation will focus on the potential adaptive roles of transcription factors, pleiotropic genes (that act in multiple biological pathways), and loss-of-function mutations (that occur at high frequency). These findings will allow us to model and predict evolutionary responses to complex environmental challenges such as those posed by climate change.

Host: Deb Bell-Pedersen