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Mathematical Biology Seminar

 

 

Tuesday, 03/19/2019, at 4:10 - 5:00

 

 

SPARK 327

 

 

 

 

Evolutionary genomics in extreme environments

 

Joanna Kelley

Associate Professor

 

 

School of Biological Sciences, WSU

 

 

 

 

 

Abstract

 

 

 

Determining whether populations evolve along the same evolutionary trajectory or whether there are multiple trajectories to reach the same outcome is a major question in evolutionary genomics. Multiple populations of Poecilia fish have adapted to hydrogen sulfide-rich springs from ancestral freshwater streams, making them an ideal system to study the reproducibility of the evolutionary process. Hydrogen sulfide (H2S) interrupts the mitochondrial respiratory chain and is also associated with severe hypoxia, and therefore highly toxic. The high level of dissolved H2S suggests that gills are one of the relevant tissues where changes associated to the adaptation to H2S might occur. RNA-sequencing data from gills provides unique evidence for the genomic and transcriptional basis of adaptation to this extreme environment. Comparing transcriptional changes across replicated pairs of sulfidic and non-sulfidic populations, we identify convergent evidence of differential expression. Moreover we demonstrate evidence for selection acting on genes underlying adaptation to the extreme environment (up-regulated in sulfidic conditions) including loci that are targets of sulfide toxicity (including COX1), involved in sulfide detoxification (sulfur dioxygenase and sulfide:quinone oxidoreductase), and hypoxia responses (myoglobin). Together, our research sheds light on the genomic basis of adaptation, speciation, and the generation of biodiversity.