These two authors have equally contributed to this manuscript.
Article first published online: 17 APR 2012
© 2012 Blackwell Publishing Ltd
Volume 21, Issue 11, pages 2743–2760, June 2012
How to Cite
CAETANO, S., CURRAT, M., PENNINGTON, R. T., PRADO, D., EXCOFFIER, L. and NACIRI, Y. (2012), Recent colonization of the Galápagos by the tree Geoffroea spinosa Jacq. (Leguminosae). Molecular Ecology, 21: 2743–2760. doi: 10.1111/j.1365-294X.2012.05562.x
- Issue published online: 24 MAY 2012
- Article first published online: 17 APR 2012
- Received 20 August 2010; revision received 9 February 2012; accepted 16 February 2012
- ABC analysis;
- founder events;
- genetic structure;
- long-distance dispersal;
This study puts together genetic data and an approximate bayesian computation (ABC) approach to infer the time at which the tree Geoffroea spinosa colonized the Galápagos Islands. The genetic diversity and differentiation between Peru and Galápagos population samples, estimated using three chloroplast spacers and six microsatellite loci, reveal significant differences between two mainland regions separated by the Andes mountains (Inter Andean vs. Pacific Coast) as well as a significant genetic differentiation of island populations. Microsatellites identify two distinct geographical clusters, the Galápagos and the mainland, and chloroplast markers show a private haplotype in the Galápagos. The nuclear distinctiveness of the Inter Andean populations suggests current restricted pollen flow, but chloroplast points to cross-Andean dispersals via seeds, indicating that the Andes might not be an effective biogeographical barrier. The ABC analyses clearly point to the colonization of the Galápagos within the last 160 000 years and possibly as recently as 4750 years ago (475 generations). Founder events associated with colonization of the two islands where the species occurs are detected, with Española having been colonized after Floreana. We discuss two nonmutually exclusive possibilities for the colonization of the Galápagos, recent natural dispersal vs. human introduction.