Abstract Detail

Molecular Ecology and Evolution

Flores , Carina Gutierrez [1], García-de-León, Francisco Javier [2], Leon-de-la-Luz, José Luís [3], Cota-Sánchez, Jorge Hugo [4].

BREEDING SYSTEM AND GENETIC DIVERSITY OF THE COLUMNAR CACTI (Pachycereus pringlei) IN NORTHWEST MEXICO.

Contemporary patterns of genetic variation are determined by historical patterns of gene flow and vicariance events (Avise, 2002). In plants, matting systems can also have an important effect on the genetic variation due to changes on recombination rates among populations (Duminil et al., 2007). The columnar arborescent cacti (Pachycereus pringlei, Britton and Rose, Cactaceae) is an excellent model for molecular studies not only because of the changing climatic conditions that characterizes its range of distribution along the southern Sonoran Desert, México, but also because it is one of the two rare species of cacti for which three breeding systems have been reported (Fleming et al., 1998, Medel-Narvaez, 2008). In this study we determined the geographical variation of breeding systems and genetic variation of P. pringlei, based on ten microsatellite markers previously designed by pyrosequencing (Gutierrez-Flores, et al., 2014) in order to evaluate the effect of both, historical climatic events and breeding systems on the contemporary genetic pattern of P. pringlei. Hermaphroditic localities were found at two islands of southern Gulf of California, gynodioecious localities (or trioecious having less than 15% males) were found along the coast of Sonora, Northern Baja California Peninsula and the east coast of Southern Baja California Peninsula; and, trioecious localities were found mainly along southern peninsula. Observed heterozygosity varied from 0.27 to 0.61 (mean Ho=0.48) and exhibited a negative correlation with latitude as well as with the frequency of hermaphrodites. A Neighbor-joining phenogram showed two main groups: 1) Southern Baja California Peninsula (SBC) and, 2) Northern Baja California-mainland Sonora (NBC-SON). The second group (NBC-SON) was serially nested within localities from middle Baja California Peninsula and subsequently by the SBCP group. These two groups were further supported by Bayesian clustering analysis (i.e. STRUCTURE) and were characterized by possessing different breeding systems (i.e. mostly gynodioecious and trioecious, respectively). Decreasing in genetic variation with increasing latitude and progressively nested populations were previously reported for other columnar cacti (i.e. Lophocereus schottii; Nason et al., 2002) with similar range of distribution to P. pringlei, and is consistent with the hypothesis of postglacial south-north colonization of the xeric plants through Baja California (Van Devender, 2002). In addition, the negative association among genetic diversity and hermaphrodites, as well as the presence of two genetically differentiated clusters with contrasting breeding systems suggests that this life history trait is playing an important role in the evolution of this species.

1 - Centro De Investigaciones Biológicas Del Noroeste, Laboratorio De Genetica Para La Conservacion, Instituto Politécnico Nacional 195 Playa Palo De Santa Rita Sur., La Paz, N/A, 23900, Mexico
2 - Centro de Investigaciones Biológicas del Noroeste, Laboratorio de Genética para la Conservación, Instituto Politécnico nacional 195 Playa Palo de Santa Rita Sur., la Paz, Baja California Sur, 23900, México
3 - Centro de Investigaciones Biológicas del Noroeste, Instituto Politécnico Nacional 195, Playa Palo De Santa Rita Sur, la Paz, Baja California Sur, 23900, Mexico
4 - University of Saskatchewan, Department of Biology, Saskatoon, SK, S7N 5E2, Canada

Keywords:
Pachycereus pringlei
Breeding System
Microsatellite.

Presentation Type: Oral Paper:Papers for Topics
Session: 11
Location: Firs North/Boise Centre
Date: Monday, July 28th, 2014
Time: 2:45 PM
Number: 11006
Abstract ID:539
Candidate for Awards:Margaret Menzel Award