title: Convergence and divergence during the adaptation to similar environments by an Australian groundsel.
abstract: Adaptation to replicate environments is often achieved through similar phenotypic solutions. Whether selection also produces convergent genomic changes in these situations remains largely unknown. The variable groundsel, Senecio lautus, is an excellent system to investigate the genetic underpinnings of convergent evolution, because morphologically similar forms of these plants have adapted to the same environments along the coast of Australia. We compared range-wide patterns of genomic divergence in natural populations of this plant and searched for regions putatively affected by natural selection. Our results indicate that environmental adaptation followed complex genetic trajectories, affecting multiple loci, implying both the parallel recruitment of the same alleles and the divergence of completely different genomic regions across geography. An analysis of the biological functions of candidate genes suggests that adaptation to coastal environments may have occurred through the recruitment of different genes participating in similar processes. The relatively low genetic convergence that characterizes the parallel evolution of S. lautus forms suggests that evolution is more constrained at higher levels of biological organization.
authors.affiliation: School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
authors.forename: Federico
authors.initials: F
authors.lastname: Roda
authors.forename: Huanle
authors.initials: H
authors.lastname: Liu
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Wilkinson
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Walter
authors.forename: Maddie E
authors.initials: ME
authors.lastname: James
authors.forename: Diana M
authors.initials: DM
authors.lastname: Bernal
authors.forename: Maria C
authors.initials: MC
authors.lastname: Melo
authors.forename: Andrew
authors.initials: A
authors.lastname: Lowe
authors.forename: Loren H
authors.initials: LH
authors.lastname: Rieseberg
authors.forename: Peter
authors.initials: P
authors.lastname: Prentis
authors.forename: Daniel
authors.initials: D
authors.lastname: Ortiz-Barrientos
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D004777:Environment; D019143:Evolution, Molecular; D049810:Genetic Speciation; D014644:Genetic Variation; D018745:Genome, Plant; D012674:Senecio / Q000235:genetics*
keywords: Adaptation; convergence; evolutionary genomics; selection-natural; senecio; speciation