About Dr. Mason-Gamer's Research
As a plant systematist, I am interested in the evolutionary processes that lead to divergence among plants, and in the phylogenetic patterns that describe relationships among them. Within this broad area, I am especially interested in using molecular genetic techniques to study phylogenetic relationships among closely related species. At this level, taxa have begun to diverge, yet often still show evidence of past or ongoing gene exchange. Closely related taxa, therefore, may show a reticulate pattern of evolution, a situation in which two divergent branches on the phylogenetic tree of life have merged back together. Reticulate patterns may result from the maintenance of gene diversity from ancestral populations (incomplete lineage sorting) or from explicitly reticulating processes such as hybridization, allopolyploidy, or horizontal gene transfer. In some groups, a combination of these may give rise to observed patterns. Obtaining evidence for reticulate evolution often requires detailed comparisons among multiple phylogenetic data sets, and this has led to my interest in the methodologies that underlie such comparisons.
Much of my current research involves the grass family, with a particular emphasis on the wheat tribe (Triticeae). Comparisons among diploid genera in this economically important group show strong evidence of gene exchange, even though the genera are currently intersterile. I am now starting to apply next generation sequence data to a broader, genome-wide assessment of patterns of phylogenetic conflict in the tribe. I also have a continuing interest in allopolyploidy in this group. I use molecular methods to address the relationships between allopolyploids and their related diploids, as well as the complicated relationships among the allopolyploid species.
Students in my lab apply phylogenetic methodology in a variety of projects. For more specific information about past and ongoing projects, visit my lab page
and meet the members of the lab.
Minaya, M., M. Pimentel, R. J. Mason-Gamer, and P. Catalán. 2013. Distribution and evolutionary dynamics of Stowaway miniature inverted repeat elements (MITEs) in grasses. Molecular Phylogenetics and Evolution; published online March 2013.
Jorgensen, M. C., P. Sierwald, and R. J. Mason-Gamer. 2013. A critical review of subspecies recognition through a literature survey of Polydesmida millipedes with a revision of the subspecies of Euryuridae. Zoologica Scripta 42:317–326.
Naum, M., E. W. Brown, and R. J. Mason-Gamer. 2011. Is a robust phylogeny of the enterobacterial plant pathogens attainable? Cladistics 27:80–93.
Mason-Gamer, R. J., M. M. Burns, and M. Naum. 2010. Reticulate evolutionary history of a complex group of grasses: phylogeny of Elymus StStHH
allotetraploids based on three nuclear genes. PLoS ONE 5:e10989.
Mason-Gamer, R. J., M. M. Burns, and M. Naum. 2010. Phylogenetic relationships and reticulation among Asian Elymus allotetraploids: analysis of three nuclear genes. Molecular Phylogenetics and Evolution 54:10-22.
Mason-Gamer, R. J. 2008. Allohexaploidy, introgression, and the complex history of Elymus repens (Poaceae). Molecular Phylogenetics and Evolution 47:598-611.
Mason-Gamer, R. J. 2007. Multiple homoplasious insertions and excisions of a Triticeae (Poaceae) DNA transposon: a phylogenetic perspective. BMC Evolutionary Biology 7:92.
Mason-Gamer, R. J. 2005. The β-amylase genes of grasses and a phylogenetic analysis of the Triticeae (Poaceae). American Journal of Botany 92:1045-1058
Helfgott, D. M. and R. J. Mason-Gamer. 2004. The evolution of North American Elymus (Triticeae, Poaceae) allotetraploids: evidence from phosphoenolpyruvate carboxylase gene sequences. Systematic Botany 29:850-861.
Mason-Gamer, R. J. 2004. Reticulate evolution, introgression, and intertribal gene capture in an allohexaploid grass. Systematic Biology 53:25-37.