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Abstract Detail



Population Genetics

Riser, James [1], Roalson, Eric [2].

Populations Genetics and Species Boundaries in the Dwarf Milkweed Group (Asclepias uncialis-ruthiae-eastwoodiana-sanjuanensis Asclepiadoideae: Apocynaceae).

Asclepias uncialis, A. ruthiae, A. sanjuanensis, and A. eastwoodiana are closely related diminutive milkweed species that occur in xeric habitats across large portions of western North America. Species boundaries and the relationships between putative species are not well understood within this small group of milkweeds. Additionally, there has been disagreement over the taxonomic status of A. ruthiae, A. sanjuanensis, and A. eastwoodiana. All four species have allopatric distributions characterized by widely scattered, small populations of stems (n=1 to >50). Genetic diversity within these populations is unknown, but may be very low due to the clonal growth common in milkweeds, i.e., a particular group of stems may actually only represent a single genotype. Conversely, Asclepias species are typically obligate outcrossers (with known exceptions); however, fruit set has been observed in many of the sampled populations. We examine intra- and inter-specific gene flow within and among these widely distributed milkweed species. By collecting samples from across each species’ range, we hope to detect any population genetic structuring and/or fine-scale genetic patterns (such as any potential hybridization). We collected a total of 971 silica-dried leaf tissue samples: nine A. eastwoodiana populations (n=264), thirteen A. ruthiae populations (n=405), eight A. sanjuanensis populations (n=121), and twelve A. uncialis populations (n=181). We are using previously developed microsatellite markers to assess intra and inter-populational genetic variation. Traditional and Bayesian-based population genetic analyses were conducted.

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1 - Washington State University, School of Biological Sciences, PO Box 644236, Pullman, WA, 99164-4236, USA
2 - Washington State University, School of Biological Sciences, Abelson Hall 339, Pullman, WA, 99164-4236, USA

Keywords:
Apocynaceae
Asclepias
population genetics
species delimitation
microsatellites.

Presentation Type: Oral Paper:Papers for Topics
Session: 40
Location: Marlborough B/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 10:30 AM
Number: 40007
Abstract ID:750
Candidate for Awards:Margaret Menzel Award

Canceled

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