Quote of the Month

"Even apparently similar adaptations may be built from genetically different components."
-Theodosius Dobzhansky

Research Statement

Pinus balfouriana subsp. austrina
The woody plant flora of North America is diverse. I use a variety of phylogeographic, biogeographic, and phylogenetic approaches with which to understand the origin and diversification of species comprising this flora. These approaches have largely focused on single species (but see Eckert and Hall 2006) with the goal of reconstructing some aspect of their demographic history (e.g. Eckert et al. 2010) or to test a specific hypothesis about the origin of some aspect of their current range distribution (e.g. Eckert et al. 2008). My approach to this area of research tends to be hypothesis driven, where multiple competing hypotheses are proposed and the best one(s) is/are chosen using some form of statistical model selection (see Eckert 2011). The outputs from these efforts are candidate models or explanations for why a particular set of populations, a species, or a set of species is distributed as it is or has a particular level of genetic diversity. These results feed naturally into the previous research interests, as phylogeographic history is by definition the history in which natural selection affects allele frequencies at the genes or genomic regions affecting fitness-related phenotypic traits. As such, inferences from this research interest are often incorporated as covariates into the analyses discussed previously. A prime example is my previous research into the phylogeographic history of foxtail pine, which identified the onset of the largest cycle of Pleistocene glaciation in California (~ 1 million years ago) as the likely driver of a 500 km range disjunction for this species (Eckert et al. 2008). This result established foxtail pine as a useful system to study the interplay between gene flow, which differs in magnitude among local stands distributed on either side of this range disjunction, and local adaptation.

Literature Cited

  • Eckert, A. J. 2011. Seeing the forest for the trees: statistical phylogeography in a changing world. New Phytologist 189: 894-897.
  • Eckert, A. J. and B. D. Hall. 2006. Phylogeny, historical biogeography, and patterns of diversification for Pinus (Pinaceae) – Phylogenetic tests of fossil-based hypotheses. Molecular Phylogenetics and Evolution 40: 166-182.
  • Eckert, A. J., B. R. Tearse, and B. D. Hall. 2008. A phylogeographical analysis of the range disjunction for foxtail pine (Pinus balfouriana, Pinaceae): the role of Pleistocene glaciation. Molecular Ecology 17: 1983-1997.
  • Eckert, A. J., M. L. Eckert and B. D. Hall. 2010. Effects of historical demography and ecological context on spatial patterns of genetic diversity within foxtail pine (Pinus balfouriana, Pinaceae) stands located in the Klamath Mountains, California. American Journal of Botany 97: 650-659.