Abstract Detail

Population Genetics

Gutiérrez Ortega, José Said [1], Kajita, Tadashi [1], Vovides, Andrew [2], Pérez Farrera, Miguel Ángel [3], Molina Freaner, Francisco E. [4].

Phylogeographic studies on the Neotropical cycad genus Dioon (Zamiaceae).

The cycad genus Dioon (Zamiaceae) comprises fourteen endangered species from Mexico and Central America. Most of Dioon species are geographically restricted and consist of small populations scattered mostly in tropical dry forests in the main mountain systems. Their discontinuous distributions have been attributed to short-distance dispersal and the historical demography through the climate changes since the Pleistocene. However, a little is certainly known about the phylogeography of this genus. Phylogeography implies both evolutionary and conservation issues. First, it may help us to describe the history of speciation and the intraspecific evolution. Besides, it provides useful information for the proposal of effective conservation plans. The aims of this study concern on these issues. Here is presented the first phylogeographic study of a Dioon species, focusing on D. sonorense. Although D. sonorense is endangered, only a portion of its southern distribution is conserved, while the rest of the populations are being affected by ilegal collection. A total of nine locations were surveyed in an extensive sampling throughout its distributional range; five locations are new records for population studies. One leaflet per individual was sampled and 77 individuals were randomly selected for further DNA analyses. The trnL-F region of the chloroplast DNA was amplified and sequenced for each individual. Only three haplotypes were identified in the entire distributional range of D. sonorense, and the genetic variation was found to be low. However, the three haplotypes were geographically structured, which may suggest that they belong to different evolutionary units. Since the northern and middle populations are not preserved, but represent unique haplotypes, their inclusion in conservation plans is strongly recommended. The study was expanded to include all the fourteen Dioon species and describe the relationships of their haplotypes in an evolutionary context. Results allow inferring general phylogeographic patterns on the genus. One haplotype showed a wide geographical distribution and was shared by eight different species from southern and eastern Mexico. As well, other shared haplotype was found in western Mexico, in D. sonorense and its sister species D. tomasellii. Haplotype sharing among species might be the result of ancestral polymorphism, or genetic introgression between species. Further analyses are being performed to describe more robustly the phylogeography of the genus Dioon.

1 - Chiba University, Department of Biology, 1-31 Yayoi-cho, Inage-ku, Chiba-shi, Chiba-ken, 263-8522, Japan
2 - Instituto de Ecología, A. C., Departamento de Biología Evolutiva, Carretera a Coatepec 351, Xalapa, Veracruz, 91070, Mexico
3 - Universidad de Ciencias y Artes de Chiapas, Facultad de Ciencias Biológicas, Libramiento Norte Poniente 1150, Tuxtla Gutiérrez, Chiapas, 29039, Mexico
4 - Instituto de Ecología, UNAM, Apartado Postal 1354, Hermosillo, Sonora, 83000, Mexico

Keywords:
phylogeography
Dioon
cycads
threatened species.

Presentation Type: Oral Paper:Papers for Topics
Session: 6
Location: Pines South/Boise Centre
Date: Monday, July 28th, 2014
Time: 9:15 AM
Number: 6004
Abstract ID:308
Candidate for Awards:Margaret Menzel Award