EnGGen: Environmental Genetics and Genomics Laboratory

Allan Lab Group (G. Allan, PI)

Research projects in my lab typically focus on population genetic and genomic studies of the tree genus, Populus (Salicaceae). Populus includes numerous ecologically and economically important species found throughout North America, Eurasia and Africa. In North America species of Populus dominate riparian ecosystems and are drivers of community and ecosystem traits (e.g, community diversity and nutrient cycling). Members of my group are studying a group of Populus species known as cottonwoods, all of which freely hybridize wherever zones of overlap are found. Hybridization in cottonwoods forms the basis for many current projects that examine: 1) population genetic structure of hybrid zones; 2) the molecular basis of ecologically important traits; 2) genetic structure and covariance between key arthropods and their cottonwood hosts; 2) the genetic basis of susceptibility to keystone arthropods via genetic introgression and; 4) the association of genetic diversity and community structure and diversity. Members of my research group work closely with members of the Cottonwood Ecology Group [www.poplar.nau.edu] in order to merge genetic and genomic information with ecological and ecosystem data, essentially a genes to ecosystems approach. The majority of this research is supported by an NSF-FIBR grant [DEB-0425908]. Individual research projects are explained in greater detail below:

Current Research Projects:

Scott Woolbright, Ph.D. candidate:
My primary interests include ecological genetics and genomics of foundation and keystone species, integrating fundamental ecological and evolutionary research with conservation and restoration (particularly those involving relict communities and ecosystems), and the evolution of novel species interactions (particularly as it relates to climate change). Here at NAU’s EnGGen facility, we’re using QTL mapping of ecologically significant traits to investigate the ways in which genes from a “foundation species” like cottonwood act to structure dependent communities and ecosystems. These include defensive chemistry, phenology, architecture, leaf morphology and other traits known to affect the distribution and abundance various associated species. I’m also looking at the potential ecological and evolutionary consequences of population fragmentation and isolation in cottonwoods following the last ice age. Cottonwood populations in the “sky island” mountains of Nevada’s Basin and Range Province consist of small, isolated stands, which likely represent the remnants of larger and more interconnected populations that existed during the last glaciation. These “ecological relicts” have survived the invasion of the Great Basin and Mojave deserts, and represent potential “natural laboratories” for studying the community- and ecosystem-level consequences of fragmentation, isolation, and, potentially, evolution in a foundation species.

Luke Evans, Ph.D. student:
My interests center on what factors drive the evolution of herbivores. I am currently studying how plant variation at the genotype, population, and species levels in the genus Populus affect the population dynamics andevolution of a dependent, herbivorous mite, Aceria parapopuli. To examine these patterns, I use a combination of molecular genetic and field and greenhouse experimenal approaches.

Nashelly Meneses, Ph.D. student:
My research interests and expertise include: Ecological genetics, plant-insect interactions (herbivory and pollination), habitat fragmentation, conservation, evolution, speciation, co-evolution. I am investigating how plant populations become genetically differentiated and how that in turn affects the dependent insect community and focal keystone herbivores. I use plant species of the genus Populus (aspen and cottonwoods). Populus species are widely distributed and can reproduce clonally or can interbreed with related species (hybridize). Cottonwoods are foundation species important for community and ecosystem processes.

Matt Zinkgraf, Ph.D. student:
My research focuses on introgressive hybridization in Populus. Introgressive hybridization is a potent evolutionary force that allows for the transfer of genes from one species to another. This process has been shown to affect species performance, resistance and can scale up to affect arthropod community organization. Currently, I am working on identifying introgressing loci that affect host plant susceptibility to a keystone herbivore, Pemphigus betae. The goal of this project is to identify potential genetic mechanisms that contribute to community organization.

Helen Bothwell, Ph.D. student:
I'm interested in exploring how broad-scale biogeographic patterns influence population genetic structure, diversity, and adaptive differentiation in flora throughout the intermountain west. Currently I am working with narrowleaf Cottonwood, thinking about our rapidly changing climate as an evolutionary agent of natural selection, and the effect this is having on plant-insect interactions.

Katie Mayer, Research Technician:
In addition to managing the EnGGen Laboratory, I work on a variety of projects involving the generation of genetic markers for ecological and population genetic studies in Cottonwoods. Research that I conduct is applied to plant-insect interactions, restoration ecology and phylogeography using different cottonwood species.

Elisa Olson, undergraduate research:
I am currently working on a study involving range wide genetic diversity and structure in Fremont cottonwood using microsatellites developed from the Populus Genome Project [http://www.ornl.gov/sci/ipgc/] . Characterizing the genetic structure of Fremont cottonwood will set the stage for conducting ecological genetic studies involving plant host (Fremont cottonwood) - insect interactions.

Former Lab Members

Barb Honchak, Master’s student
I conducted a study of genetic variation in Fremont cottonwood using AFLPs. Results from my study showed that Fremont cottonwood is very diverse and exhibits high among population genetic structure. This is one of the first range wide studies of population genetic structure of any North American species of Populus. The title of my Master’s thesis is “Genetic Diversity and Structure of a Foundation Riparian Forest Tree, Populus fremontii.