title: Genetic variation (AFLPs and nuclear microsatellites) in two anagenetically derived endemic species of Myrceugenia (Myrtaceae) on the Juan Fernández Islands, Chile.
abstract: OBJECTIVE
  Anagenesis (or phyletic evolution) is one mode of speciation that occurs in the evolution of plants on oceanic islands. Of two endemic species on the Juan Fernández Islands (Chile), Myrceugenia fernandeziana and M. schulzei (Myrtaceae), believed to have originated anagenetically from different continental progenitors, the first is endemic to Robinson Crusoe Island and has no clear tie to continental relatives; the last is endemic to the younger island, Alejandro Selkirk Island, and has close affinity to M. colchaguensis in mainland Chile.
  
  
  METHODS
  Using AFLPs and six nuclear microsatellites from 381 individuals representing 33 populations, we determined patterns of genetic variation within and among populations on both islands and between those of the islands and mainland.
  
  
  RESULTS
  Considerable genetic variation was found within populations on both islands. The level of gene diversity within M. schulzei was equivalent to that of its close continental relative M. colchaguensis. Genetic diversity was not partitioned geographically in M. fernandeziana and was weakly so and nonsignificantly in M. schulzei.
  
  
  CONCLUSIONS
  The high genetic variation in both taxa is most likely due to anagenetic speciation. Subsidence of the older island Robinson Crusoe, landscape erosion, and restructuring of communities have severely reduced the overall island population to a single panmictic system. On the younger and less modified Alejandro Selkirk Island, slightly stronger patterns of genetic divergence are seen in M. schulzei. Because both species are genetically diverse and number in the thousands of individuals, neither is presently endangered in the archipelago.
authors.affiliation: Department of Systematic and Evolutionary Botany, Biodiversity Center, University of Vienna, Rennweg 14, A-1030 Vienna, Austria.
authors.forename: Patricio
authors.initials: P
authors.lastname: López-Sepúlveda
authors.forename: Koji
authors.initials: K
authors.lastname: Takayama
authors.forename: Josef
authors.initials: J
authors.lastname: Greimler
authors.forename: Patricio
authors.initials: P
authors.lastname: Peñailillo
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Crawford
authors.forename: Marcelo
authors.initials: M
authors.lastname: Baeza
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ruiz
authors.forename: Gudrun
authors.initials: G
authors.lastname: Kohl
authors.forename: Karin
authors.initials: K
authors.lastname: Tremetsberger
authors.forename: Alejandro
authors.initials: A
authors.lastname: Gatica
authors.forename: Luis
authors.initials: L
authors.lastname: Letelier
authors.forename: Patricio
authors.initials: P
authors.lastname: Novoa
authors.forename: Johannes
authors.initials: J
authors.lastname: Novak
authors.forename: Tod F
authors.initials: TF
authors.lastname: Stuessy
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D002677:Chile; D014644:Genetic Variation; D018895:Microsatellite Repeats; D027822:Myrtaceae / Q000235:genetics*; D058974:Phylogeography