The role of gene expression in ecological speciation.
Bottom Line: Gene expression may be associated with ecologically important phenotypes not evident from morphology and play a role during colonization of new environments.We also find clear examples of gene expression having effects on phenotypic traits and adaptive genetic divergence, but links to the evolution of reproductive isolation itself remain indirect.The study of gene expression has promise for increasing our understanding ecological speciation, particularly when integrative approaches are applied.
Affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.Show MeSH
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Mentions: The first manner in which gene expression might affect speciation is via promoting population persistence. As exemplified by Baldwin's quotation above, once a population colonizes a new environment, it must persist if it is to speciate. Population establishment and persistence in a new environment may be facilitated by phenotypic plasticity (Fig. 2).86–90 Modulation of behavioral, morphological, or physiological traits via phenotypic plasticity could therefore occur before any adaptive genetic evolution occurs.23 Gene expression-mediated phenotypic plasticity may be described as reaction norms in gene expression with the molecular phenotype of gene expression-facilitating population persistence following colonization.30 Direct tests of this idea are lacking, but two lines of indirect evidence exist: (1) studies of plasticity in traits (morphology and behavior mostly) related to fitness and population persistence and (2) studies of gene expression responses during ecological shifts, particularly those resulting in exposure to ecological stress.
Affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.