title: Progressive migration and anagenesis in Drimys confertifolia of the Juan Fernández Archipelago, Chile.
abstract: A common mode of speciation in oceanic islands is by anagenesis, wherein an immigrant arrives and through time transforms by mutation, recombination, and drift into a morphologically and genetically distinct species, with the new species accumulating a high level of genetic diversity. We investigate speciation in Drimys confertifolia, endemic to the two major islands of the Juan Fernández Archipelago, Chile, to determine genetic consequences of anagenesis, to examine relationships among populations of D. confertifolia and the continental species D. winteri and D. andina, and to test probable migration routes between the major islands. Population genetic analyses were conducted using AFLPs and nuclear microsatellites of 421 individuals from 42 populations from the Juan Fernández islands and the continent. Drimys confertifolia shows a wide genetic variation within populations on both islands, and values of genetic diversity within populations are similar to those found within populations of the continental progenitor. The genetic results are compatible with the hypothesis of high levels of genetic variation accumulating within anagenetically derived species in oceanic islands, and with the concept of little or no geographical partitioning of this variation over the landscape. Analysis of the probability of migration within the archipelago confirms colonization from the older island, Robinson Crusoe, to the younger island Alejandro Selkirk.
authors.affiliation: Departamento de Botánica, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
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: Daniel J
authors.initials: DJ
authors.lastname: Crawford
authors.forename: Patricio
authors.initials: P
authors.lastname: Peñailillo
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; D032424:Drimys / Q000235:genetics*; D049810:Genetic Speciation; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D062312:Islands; D018895:Microsatellite Repeats / Q000235:genetics; D008954:Models, Biological; D010802:Phylogeny