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Abstract Detail

Recent Topics Posters

Wagner, Carl [1], Boutte, Julien [1], Fishbein, Mark [2], Straub, Shannon [1].

Phylogeny of a Temperate North American Clade of Milkweeds (Asclepias) and Positive Selection on the Plastid ycf4 Gene.

North American milkweeds (Asclepias) have experienced recent rapid diversification. Next generation sequencing provides a tool to economically produce the large data sets necessary to resolve the relationships of recently diverged species. Previous studies of plastomes have largely resolved the matrilineal phylogeny of this group, but with only one sample per species. This study aims to determine if closely related milkweed species in a temperate North American clade are reciprocally monophyletic. Utilizing Illumina paired-end sequences, the chloroplast genomes of 106 individuals from 20 different species were assembled de novo and used to infer a phylogenetic tree in a maximum likelihood framework. Of the twelve species with multiple samples, 10 were reciprocally monophyletic. However, two species, A. exaltata and A. lanceolata, were polyphyletic. Among the clades of A. exaltata samples, geographic patterns were evident with one group containing individuals from coastal populations and another containing individuals from inland populations. The three groupings of A. lanceolata individuals were also geographically isolated. Further, examination of the plastid gene ycf4 in this subclade during alignment, revealed high levels of variation compared to the remainder of the plastome. Using a Fixed Effects Likelihood test (FEL) comparing the ratio of synonymous and nonsynonymous mutations, two sites showed strong positive selection and three sites showed strong purifying selection. Changes in ycf4 have been linked to photosynthetic efficiency.

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1 - Hobart and William Smith Colleges, Department of Biology, 300 Pulteney St., Geneva, NY, 14456, USA
2 - Oklahoma State University, Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Stillwater, OK, 74078, USA

positive selection.

Presentation Type: Recent Topics Poster
Session: P, Recent Topics Posters
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM
Number: PRT018
Abstract ID:1308
Candidate for Awards:None

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