Abstract Detail

Population Genetics/Genomics

Willis, Alison [1], Fehlberg, Shannon [2].

Analysis of genetic diversity and clarification of species boundaries of Echinomastus erectocentrus var. acunensis (Cactaceae) and close relatives.

The Acuña cactus, Echinomastus erectocentrus var. acunensis, is an endangered cactus species with a restricted distribution in the Sonoran Desert in southern Arizona and into northern Sonora, Mexico. Population level genetic analyses for this species are lacking, and the exact level of genetic distinctiveness between E. erectocentrus var. acunensis and its close relatives is unclear. Populations of E. erectocentrus found north of Tucson, Arizona are geographically, morphologically, and ecologically intermediate between the two varieties, E. erectocentrus var. acunensis and E. erectocentrus var. erectocentrus. The varieties of E. erectocentrus are also replaced to the northwest by E. johnsonii, and these taxa are only weakly differentiated morphologically. Detailed morphological data that have been collected on these three taxa indicate the existence of a geographical cline from the northern Mojave Desert to the northern Sonoran Desert. The goal of this project is to document the genetic diversity found within and among populations of E. erectocentrus var. acunensis, as well as between E. erectocentrus var. acunensis and its close relatives E. erectocentrus var. erectocentrus and E. johnsonii. To accomplish this, seven known populations of E. erectocentrus var. acunensis, three populations of E. erectocentrus var. erectocentrus and four populations of E. johnsonii were visited. At each population, tepals from at least 12 distinct individuals were sampled for a total of 230 samples. DNA was extracted, and data were collected for 11 microsatellite regions developed specifically for these taxa, and two microsatellite regions developed previously for Sclerocactus. Standard population genetic measures were used to determine genetic variation and structure, and this observed genetic differentiation was then compared to the current morphological understanding of the group. These analyses help improve our knowledge of the genetic structure of E. erectocentrus var. acunensis and inform our understanding of species boundaries, and evolutionary relationships within the group. This information also reveals patterns of gene flow and population locations that have the highest conservation priority, which can be incorporated into efforts to conserve and protect this endangered species.

1 - Arizona State University, School of Life Sciences, PO Box 874501, Tempe, AZ, 85287, USA
2 - Desert Botanical Garden, Research, Conservations, and Collections, 1201 North Galvin Parkway, Phoenix, AZ, 85008, United States

Keywords:
population genetics
conservation
Endangered
species delimitation
Cactaceae
Echinomastus.

Presentation Type: Poster
Session: P, Population Genetics/Genomics Posters
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPG007
Abstract ID:464
Candidate for Awards:Genetics Section Poster Award