Abstract Detail

Population Genetics

Hubbard, Ashley [1], McGlaughlin, Mitchell E. [2], RampNeale, Jennifer [3].

Examination of Sclerocactus wetlandicus and Sclerocactus brevispinus Genetic Diversity and Population Structure in the Uinta Basin, Utah.

Sclerocactus wetlandicus and S. brevispinus are two federally threatened cacti species endemic to the Uinta Basin, Utah. Traditional methods of taxonomic classification, based primarily on morphology, have lead to taxonomic confusion within Sclerocactus. Sclerocactus are challenging to distinguish in the field due to varying phenotypes across species distributions, warranting genetic investigation, independent of morphology and geography. Understanding species circumscription, genetic diversity, and population structure are essential to ensure threatened and endangered species receive optimal conservation and that unique genetic entities are correctly identified. Twelve variable microsatellite markers were examined to quantify Uinta Basin Sclerocactus genetic diversity and population structure. Previously classified as two distinct species, we observed that geography influenced genetic differentiation more than morphology based species circumscription. We suggest that S. wetlandicus and S. brevispinus are not separate species but all sampled populations show signs of divergence east and west of the Green River. The pattern of distinct genetic clusters on opposite ends of the Sclerocactus distribution were supported by Bayesian STRUCTURE cluster assignment of two genetic groups with populations centrally located showing signal of hybridization, regardless of species circumscription. Analysis of molecular variance (AMOVA) results confirm that 96.83% of genetic variation is not attributed to current species groups; rather the largest percentages were observed in intra-population comparisons at 86.11%. Genetic variation within western and eastern groups 5.22% was larger than current species groups at 3.17%, supporting that geography accounts for more variation than species groups.  Comparative chloroplast DNA analyses from two variable chloroplast regions, trnC-rpoB and trnF-trnL, were also examined to assess phylogenetic relationships and taxonomic classifications. Chloroplast data demonstrated unresolved relationships between S. wetlandicus and S. brevispinus, while S. parviflorus, a sister species, was resolved as distinct. Based on available data, S. wetlandicus and S. brevispinus are genetically undistinguishable as currently circumscribed.

1 - 802 E.21st Street, Greeley, CO, 80631, USA
2 - University Of Northern Colorado, 501 20th St, Box 92, Greeley, CO, 80639, USA
3 - Denver Botanical Gardens, Director of Research and Conservation, 1007 York Street, Denver, CO, 80206, USA

Keywords:
Sclerocactus
Conversation
Microsatellite
chloroplast.

Presentation Type: Oral Paper:Papers for Topics
Session: 6
Location: Pines South/Boise Centre
Date: Monday, July 28th, 2014
Time: 11:15 AM
Number: 6011
Abstract ID:642
Candidate for Awards:Margaret Menzel Award