title: Some rare Indo-Pacific coral species are probable hybrids.
abstract: BACKGROUND
  Coral reefs worldwide face a variety of threats and many coral species are increasingly endangered. It is often assumed that rare coral species face higher risks of extinction because they have very small effective population sizes, a predicted consequence of which is decreased genetic diversity and adaptive potential.
  
  
  RESULTS
  Here we show that some Indo-Pacific members of the coral genus Acropora have very small global population sizes and are likely to be unidirectional hybrids. Whether this reflects hybrid origins or secondary hybridization following speciation is unclear.
  
  
  CONCLUSIONS
  The interspecific gene flow demonstrated here implies increased genetic diversity and adaptive potential in these coral species. Rare Acropora species may therefore be less vulnerable to extinction than has often been assumed because of their propensity for hybridization and introgression, which may increase their adaptive potential.
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.
authors.forename: Zoe T
authors.initials: ZT
authors.lastname: Richards
authors.forename: Madeleine J H
authors.initials: MJ
authors.lastname: van Oppen
authors.forename: Carden C
authors.initials: CC
authors.lastname: Wallace
authors.forename: Bette L
authors.initials: BL
authors.lastname: Willis
authors.forename: David J
authors.initials: DJ
authors.lastname: Miller
mesh_terms: D000483:Alleles; D000818:Animals; D037421:Anthozoa / Q000502:physiology*; D003001:Cloning, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D007438:Introns; D008957:Models, Genetic; D009792:Oceans and Seas; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA