Abstract Detail

Population Genetics

Wenzel, Aaron [1], Wolfe, Andrea D. [2].

Population genetics, systematics, and phylogeography of Penstemon linarioides (Plantaginaceae), a widespread and variable species from western North America.

Penstemon linarioides (Plantaginaceae) is a species native to the Intermountain Region of western USA, having a large distribution that ranges from southern Arizona and New Mexico to southern Utah and Colorado. It also contains five subspecies that represent slight morphological variants seen throughout its range. However, questions have remained as to (1) the relationships between these subspecies and (2) the potential presence of more subspecies, especially in the variable subsp. sileri from southwest Utah and Arizona (Holmgren 1984). This study presents the results from a population genetics study of P. linariodies using seven Penstemon-specific microsatellite loci. 22 populations were included in the study, with most sampling including the subspecies linarioides, coloradoensis, and sileri; one population of subsp. compactifolius was included as well. Measures of within-population genetic diversity were relatively high, although populations of subsp. coloradoensis consistently showed lower measures of allelic richness, number of alleles, and observed/expected heterozygosity compared to subspecies linarioides and sileri. Subspecies coloradoensis also had higher (and significant) values of the inbreeding coefficient (F_IS=0.27) relative to subspecies linarioides (0.15) and sileri (0.10). AMOVA found evidence for limited population structure in P. linarioides (71% of variance distributed within individuals); however, results from a Neighbor-joining tree, principle coordinates analysis, and STRUCTURE revealed that populations consistently clustered with one another according to subspecies. These analyses also revealed a close relationship between subspecies linarioides and coloradoensis. There was evidence for additional clusters within subsp. sileri, with populations forming three clusters: one for the Bull Valley/Pine Valley Mountains in southwest Utah, one for the Markagunt Plateau further to the east, and one for the Kaibab Plateau in northern Arizona. Finally, a historical demographic analysis using Approximate Bayesian computation (ABC) found that the historical scenario with the highest posterior probability involved an ancestral population of subsp. sileri that gave rise to a lineage that ultimate split to form subspecies linarioides and coloradoensis. Using estimates of divergence times from the analysis places the timing of these events during the end of the Pleistocene, when a warming/changing climate had significant impacts on the evolution of many organisms.

1 - Ohio State University, EEOB, 318 W. 12th Ave, Columbus, Ohio, 43210, United States
2 - Ohio State University, Department Of Ecology, Evolution, And Organismal Biology, 318 W. 12th Avenue, COLUMBUS, OH, 43210-1293, USA

Keywords:
Penstemon
Microsatellite
population genetics
Phylogeography
Systematics
approximate bayesian computation
Intermountain Region.

Presentation Type: Oral Paper
Session: 39, Population Genetics
Location: 201/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 8:00 AM
Number: 39001
Abstract ID:610
Candidate for Awards:None