Jason Holliday

Synopsis:

We are broadly interested in the causes and consequences of genomic variation in forest tree species. Specifically, we address questions of demographic history and local adaptation in both gymnosperm and angiosperm trees, including spruce, pine, poplar (Populus) and chestnut.

Description:

Forest tree populations are reasonably well-adapted to their local environments at present, but anthropogenic climate change is substantially altering adaptive landscapes, particularly in temperate and boreal regions. In the absence of adaptation to rapid changes in climatic, tree populations will be forced to either migrate or be extirpated. As it is unlikely that migration rates will be sufficient to realize the range shifts predicted by climate-based species distribution models, the importance of adaptive evolution cannot be underestimated. In order to predict the potential for adaptation in the context of climate change, one must first have an understanding of the genomic underpinnings of the relevant traits.

The overarching goal of our research is to understand the environmental and historical factors that contribute to adaptation in temperate and boreal tree species. To do this, we use genotype-phenotype association studies, landscape genomics, and evolutionary modeling. We leverage 'next gen' sequencing of large, diverse tree populations, which are grown in common environments and measured for a variety of adaptive traits, including timing of growth and dormancy transitions, tolerance to temperature extremes and drought hardiness. We are currently applying this approach in the Populus genus, and have also worked with economically and ecologically important conifers such as spruce and pine. We are also using genomics to accelerate American chestnut breeding for resistance to an introduced fungal blight that decimated this ecologically important species a century ago.

A better understanding of the genomic underpinnings of complex adaptive traits facilitates predictions of carbon sequestration in future forests, enhances the adaptive potential of local populations through conservation of ecologically-relevant genetic variation, and facilitates sustainable production of wood biomass through genome-enabled breeding. More generally, these studies begin to provide answers to long-standing questions in evolutionary ecology about the genetic architecture of adaptation.