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Abstract Detail


Mikenas, Jessica [1], Croley, Matthew [1], Goodman, Arianna [1], Brunner, Anna [1], Stalberg, Gabriel [1], Douglas, Norman [2], Flores Olvera, Hilda [3], Ochoterena, Helga [3], Moore, Michael J. [2].

Phylogeography of the gypsophilic clade of Acleisanthes (Nyctaginaceae).

The Chihuahuan Desert, located in the southwestern United States and northern Mexico, contains numerous gypsum deposits that are scattered throughout the region. On these exposed and discontinuous patches of gypsum substrate, a diverse array of endemic plants can be found, referred to as “gypsophiles.” Many of the dominant gypsophilic species in the Chihuahuan Desert are broadly distributed despite the island-like nature of exposed gypsum.  Moreover, these regionally dominant taxa often belong to clades of gypsophiles, with the taxa in these clades allopatrically distributed.  The genus Acleisanthes provides an excellent example of this pattern.  Of the approximately 17 species in the genus, six belong to a single clade of gypsophiles that collectively are distributed throughout most of the Chihuahuan Desert region.
A recent molecular dating analysis suggests that the gypsophilic clade of Acleisanthes originated in the Pliocene, implying that the clade has persisted through the wetter and cooler pluvial periods of the Pleistocene, when landscape-scale arid habitats disappeared from the Chihuahuan Desert region.  It is unclear, however, whether populations of gypsophilic Acleisanthes persisted broadly during the Pleistocene or were restricted to one or a few refugia. To address this question, we sequenced four chloroplast spacer regions and nuclear ITS for 170 populations of Acleisanthes, including all species in the genus and multiple populations for most species, with a focus on the gypsophilic clade (90 populations).  We found a sharp north-to-south gradient of haplotype diversity in both nuclear and chloroplast DNA, with almost no haplotype diversity in the US but high levels in Mexico.  We hypothesize that this pattern results from asymmetric survival of populations in Mexico vs. the US due to the drier and warmer conditions that prevailed during pluvial periods in the Mexican portions of the Chihuahuan Desert.

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Phylogeny and phylogeography of Chihuahuan Desert gypsum endemics

1 - Oberlin College, Department of Biology, 119 Woodland St, Oberlin, OH, 44074, USA
2 - Oberlin College, Department of Biology, 119 Woodland St., Oberlin, OH, 44074, USA
3 - Universidad Nacional Autónoma de México, Instituto de Biología, Circuito exterior, Ciudad Universitaria, México, DF, CP 04510, México

Chihuahuan Desert

Presentation Type: Poster:Posters for Topics
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PBG014
Abstract ID:731
Candidate for Awards:None

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