title: Rapid evolution of coral proteins responsible for interaction with the environment.
abstract: BACKGROUND
  Corals worldwide are in decline due to climate change effects (e.g., rising seawater temperatures), pollution, and exploitation. The ability of corals to cope with these stressors in the long run depends on the evolvability of the underlying genetic networks and proteins, which remain largely unknown. A genome-wide scan for positively selected genes between related coral species can help to narrow down the search space considerably.
  
  
  RESULTS
  We screened a set of 2,604 putative orthologs from EST-based sequence datasets of the coral species Acropora millepora and Acropora palmata to determine the fraction and identity of proteins that may experience adaptive evolution. 7% of the orthologs show elevated rates of evolution. Taxonomically-restricted (i.e. lineage-specific) genes show a positive selection signature more frequently than genes that are found across many animal phyla. The class of proteins that displayed elevated evolutionary rates was significantly enriched for proteins involved in immunity and defense, reproduction, and sensory perception. We also found elevated rates of evolution in several other functional groups such as management of membrane vesicles, transmembrane transport of ions and organic molecules, cell adhesion, and oxidative stress response. Proteins in these processes might be related to the endosymbiotic relationship corals maintain with dinoflagellates in the genus Symbiodinium.
  
  
  CONCLUSIONS
  This study provides a birds-eye view of the processes potentially underlying coral adaptation, which will serve as a foundation for future work to elucidate the rates, patterns, and mechanisms of corals' evolutionary response to global climate change.
authors.affiliation: Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia. christian.voolstra@kaust.edu.sa
authors.forename: Christian R
authors.initials: CR
authors.lastname: Voolstra
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sunagawa
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Matz
authors.forename: Till
authors.initials: T
authors.lastname: Bayer
authors.forename: Manuel
authors.initials: M
authors.lastname: Aranda
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Buschiazzo
authors.forename: Michael K
authors.initials: MK
authors.lastname: Desalvo
authors.forename: Erika
authors.initials: E
authors.lastname: Lindquist
authors.forename: Alina M
authors.initials: AM
authors.lastname: Szmant
authors.forename: Mary Alice
authors.initials: MA
authors.lastname: Coffroth
authors.forename: Mónica
authors.initials: M
authors.lastname: Medina
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000818:Animals; D037421:Anthozoa / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D005075:Biological Evolution; D016000:Cluster Analysis; D017753:Ecosystem; D004777:Environment; D020869:Gene Expression Profiling; D014644:Genetic Variation; D023281:Genomics / Q000379:methods; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D013045:Species Specificity
chemical_list: D011506:Proteins