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Abstract Detail

Systematics Section

Diazgranados, Mauricio [1], Sanchez, Carolina [1], Barber, Janet C. [1].

Evaluation of microsatellite motifs for phylogenetic reconstruction in the subtribe Espeletiinae Cuatrec. (Compositae).

Neotropical taxa of high mountain ecosystems offer the opportunity of studying rapid adaptive radiations and speciation mechanisms. The páramo ecosystem, located above 3,000 m of elevation in Colombia, Venezuela, Ecuador and Costa Rica, is a relatively young (2-4 million years) ecosystem, but hosts the highest diversity of animals and plants of any high-elevation ecosystem worldwide. The subtribe Espeletiinae Cuatrec. (Asteraceae), an endemic group of the páramos, comprises more than 143 species and exhibits a remarkably high speciation rate and short time for speciation (TFSln: <0.27-0.55 species per million years). Despite very low genetic inter-specific variation, the subtribe shows an outstanding level of morphological variation. Previous and current attempts to reconstruct phylogenetic relationships within the subtribe using direct sequencing data have shown little or no resolution within major clades, and combination of regions is sometimes questionable and/or does not solve entirely the problem of low phylogenetic resolution. Our goal is to test several microsatellite motifs with putative utility for phylogenetic reconstructions. Microsatellites (a.k.a. short tandem repeats, STRs), are believed to be highly specific to taxonomic groups; therefore, developing them from a genomic library is generally needed. We have screened nine microsatellite loci developed for Helianthus: one mono-, seven di-, and one trimeric repeat loci. For each locus, annealing temperature, magnesium chloride and cycling number were optimized. After PCR optimizations, 100% successful amplifications were obtained in a set of pilot species of Espeletiinae. Fifty-five percent of these loci are polymorphic between the tested species, suggesting high potential utility for phylogenetic reconstruction. Contrary to published claims about the lack of conservation of primer sequences for microsatellite loci across the Asteraceae, our results suggest that these flanking sequences may be more conserved than previously believed.

Broader Impacts:
The outcomes of this research will benefit other researchers studying species of Espeletiinae by providing protocols, primer sequences and putative utility for microsatellite loci in this group.

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Related Links:
The Espeletia Project

1 - Saint Louis University, Department of Biology, 3507 Laclede Ave., St. Louis, MO, 63103-2010, USA

Simple Sequence Repeats (SSRs)

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM
Number: PSY003
Abstract ID:736

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