Abstract Detail

Systematics Section/ASPT

Mason-Gamer, Roberta [1], Ree, Richard [2].

Assessment of phylogenetic conflict in the wheat tribe (Poaceae: Triticeae) using next-generation genomic sequence data.

The wheat tribe, Triticeae, has been the subject of numerous molecular phylogenetic analyses since the mid-1990s. These revealed extensive phylogenetic conflict among gene trees involving relationships among genera, even when known reticulate taxa such as allopolyploids were excluded. This conflict has generally been interpreted as a result of past gene exchange, either through rare intergeneric hybridization among diploids, or through triploid bridges between allopolyploids and diploids. It is difficult to assess the overall magnitude of the conflict, both because the number of available gene trees, even for this well-studied group, is limited, and because some trees or portions of trees lack strong support. Thus, whether the observed conflict represents a small number of isolated events affecting a few chromosomal regions, vs. a more pervasive genome-wide phenomenon, remains to be seen. We collected high-throughput genomic sequence data from reduced-representation libraries obtained through size-selection of restriction-enzyme digested DNA. Samples include fourteen diploid individuals representing twelve genera. Putative orthologs were identified using within- and among-sample clustering, and tree concordance methods were used to analyze the set of phylogenetic trees generated from each locus. These analyses were used to identify primary, secondary and more minor phylogenetic histories, and thus begin to quantify the extent of phylogenetic conflict in the Triticeae. In the future, we intend to associate loci and their phylogenetic patterns with their locations within the genome (using reference genomes from Brachypodium and/or Hordeum), thus revealing whether there is a spatial pattern to the distribution of phylogenetic signal within the genome.

Broader Impacts:

1 - University of Illinois Chicago, DEPT. OF BIOLOGICAL SCIENCES (M/C 066), 845 W. TAYLOR ST., CHICAGO, IL, 60607, USA
2 - Field Museum of Natural History, Botany, 1400 S Lake Shore Drive, Chicago, IL, 60605, USA

Keywords:
Phylogenetic incongruence
Poaceae
Triticeae.

Presentation Type: Oral Paper:Papers for Sections
Session: 48
Location: Elmwood/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 5:15 PM
Number: 48015
Abstract ID:757
Candidate for Awards:None