2
|
López-Sepúlveda P, Takayama K, Greimler J, Crawford DJ, Peñailillo P, Baeza M, Ruiz E, Kohl G, Tremetsberger K, Gatica A, Letelier L, Novoa P, Novak J, Stuessy TF. Progressive migration and anagenesis in Drimys confertifolia of the Juan Fernández Archipelago, Chile. JOURNAL OF PLANT RESEARCH 2015; 128:73-90. [PMID: 25292282 PMCID: PMC4300435 DOI: 10.1007/s10265-014-0666-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 06/12/2014] [Indexed: 05/23/2023]
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.
Collapse
Affiliation(s)
| | - Koji Takayama
- The University Museum, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Josef Greimler
- Department of Systematic and Evolutionary Botany, Biodiversity Center, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Daniel J. Crawford
- Department of Ecology and Evolutionary Biology and the Biodiversity Institute, University of Kansas, Lawrence, KS 60045, USA
| | - Patricio Peñailillo
- Instituto de Biología Vegetal y Biotecnología, Universidad de Talca, 2 Norte 685, Talca, Chile
| | - Marcelo Baeza
- Departamento de Botánica, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Eduardo Ruiz
- Departamento de Botánica, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Gudrun Kohl
- Department of Systematic and Evolutionary Botany, Biodiversity Center, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Karin Tremetsberger
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Gregor Mendel Straße 33, 1180 Vienna, Austria
| | - Alejandro Gatica
- Laboratorio de Ecofisiología Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de La Serena, Casilla 599, La Serena, Chile
| | - Luis Letelier
- Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, C.P. 58190 Morelia, Michoacán Mexico
| | - Patricio Novoa
- Jardín Botánico de Viña del Mar, Corporación Nacional Forestal, Camino El Olivar 305, Viña del Mar, Chile
| | - Johannes Novak
- Institute for Applied Botany and Pharmacognosy, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Tod F. Stuessy
- Herbarium, Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 1315 Kinnear Road, Columbus, OH 43212, USA
| |
Collapse
|
3
|
Mok HF, Stepien CC, Kaczmarek M, Albelo LR, Sequeira AS. Genetic status and timing of a weevil introduction to Santa Cruz Island, Galapagos. J Hered 2014; 105:365-80. [PMID: 24399746 DOI: 10.1093/jhered/est096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Successful invasive species can overcome or circumvent the potential genetic loss caused by an introduction bottleneck through a rapid population expansion and admixture from multiple introductions. We explore the genetic makeup and the timing of a species introduction to Santa Cruz Island in the Galápagos archipelago. We investigate the presence of processes that can maintain genetic diversity in populations of the broad-nosed weevil Galapaganus howdenae howdenae. Analyses of combined genotypes for 8 microsatellite loci showed evidence of past population size reductions through moment and likelihood-based estimators. No evidence of admixture through multiple introductions was found, but substantial current population sizes (N0 298, 95% credible limits 50-2300), genetic diversity comparable with long-established endemics (Mean number of alleles = 3.875), and lack of genetic structure across the introduced range (F ST = 0.01359) could suggest that foundations are in place for populations to rapidly recover any loss of genetic variability. The time estimates for the introduction into Santa Cruz support an accidental transfer during the colonization period (1832-1959) predating the spurt in human population growth. Our evaluation of the genetic status of G. h. howdenae suggests potential for population growth in addition to our field observations of a concurrent expansion in range and feeding preferences towards protected areas and endemic host plants.
Collapse
Affiliation(s)
- Hoi-Fei Mok
- the Department of Biological Sciences, Wellesley College, Wellesley
| | | | | | | | | |
Collapse
|