Abstract Detail

Systematics Section/ASPT

López-Sepúlveda, P. [1], Takayama, K. [2], Crawford, Daniel J. [3], Greimler, J. [4], Peñailillo, P. [5], Baeza, Carlos M. [1], Ruiz, E. [1], Kohl, G. [6], Tremetsberger, K. [7], Gatica, A. [8], Letelier, L. [9], Novoa, P. [10], Novak, J. [11], Stuessy, Tod F. [12].

Speciation and biogeography of Rhaphithamnus venustus (Verbenaceae) in the Juan Fernández archipelago, Chile: a perspective from simple sequence repeat and AFLP markers.

The genus Rhaphithamnus (Verbenaceae) consists of two species, R. spinosus in continental South America, and the Juan Fernández archipelago endemic R. venustus. Rhaphithamnus venustus occurs on two islands of the archipelago, the older Robinson Crusoe (RC) is closer to the continent than the younger island of Alejandro Selkirk (AS). The two species are sister in a strongly supported clade, but their relationships within Verbenaceae are obscure. The insular species has likely evolved from the continental species or from a common ancestor of the two species, and it has been assumed that there was initial colonization of RC and subsequent dispersal to AS. The island species differs from the continental species primarily by floral traits associated with hummingbird pollination, and the evolution of gynodioecy. Prior studies demonstrated low divergence between the species at allozyme loci, and in nuclear and plastid sequences. Also, there is much lower allozyme diversity in populations of the insular than the continental species. In the present study, simple sequence repeats (SSRs) and AFLPs were used to assess genetic diversity within and divergence between the two species of Rhaphithamnus. One purpose was to compare diversity between the continental and island species, and between populations of R. venustus on RC and AS. A second objective was to assess divergence among populations, both within and between the two islands, and between the islands and the continent. Several measures of genetic diversity using both SSRs and AFLPs revealed comparable or higher diversity in the continental than the insular species. AFLPs show higher diversity in RC than in AS, but the reverse in true with SSRs. Genetic divergence is higher between plants in the different islands than it is between the continental and the island species, although this is more pronounced for SSRs than for AFLPs. Total evidence suggests that lower diversity in the island species is due to genetic bottlenecks associated with colonization of the archipelago, although other possible explanations will be discussed. Alternative explanations for higher divergence between the populations in the two islands as compared to between the insular and continental species will be presented.

1 - Universidad de Concepción, Departamento de Botánica, Casilla 160-C, Concepción, Chile
2 - 7-3-1 Hongo, Bunkyo-ku, The University Museum, The University Of Tokyo, Tokyo, N/A, 113-0033, Japan
3 - University of Kansas, Ecology and Evolutionary Biology and Biodiversity Institute, 1200 Sunnyside Ave, Lawrence, KS, 66045, USA
4 - University of Vienna, Department of Botany and Biodiversity Research, Rennweg 14, Vienna, A-1030 , Austria
5 - Universidad de Talca, Instituto de Ciencias Biológicas, 2 Norte 685, Talca, Chile
6 - University of Vienna, Department of Botany and Biodiversity Research, Rennweg 14, Vienna, Austria
7 - University of Natural Resources and Life Sciences, Department of Integrative Biology and Biodiversity Research, Gregor Mendel Straße 33, Vienna, A-1180 , Austria
8 - Universidad de La Serena, Departamento de Biología, Casilla 599, La Serena, Chile
9 - Universidad Nacional Autónoma de México, Centro de Investigaciones en Ecosistemas, Morelia, Michoacán, Mexico
10 - Jardín Botánico de Viña del Mar, Camino El Olivar 305, Viña del Mar, Chile
11 - University of Veterinary Medicine, Department Farm Animals and Veterinary Public Health, Veterinärplatz 1, Vienna, A-1210 , Austria
12 - The Ohio State University, Evolution, Ecology, and Organismal Biology, Herbarium and Museum of Biological Diversity, 1315 Kinnear Road, Columbus, OH, 43212, USA

Keywords:
 Juan Fernandez Islands
speciation
genetic diversity
Rhaphithamnus.

Presentation Type: Oral Paper:Papers for Sections
Session: 60
Location: Salon 2/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:15 AM
Number: 60002
Abstract ID:304
Candidate for Awards:None