Briana L. Gross
Postdoctoral Research Associate
brianagross(at)me.com
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What evolutionary forces govern the patterns of diversity found in nature? What are the relative contributions of deterministic and stochastic forces to processes such as speciation and species divergence? Deterministic forces (such as natural selection) and stochastic processes (such as genetic drift) can both potentially be important in shaping the origin of a species and evolution of a lineage, but the relative contribution of each force is difficult to determine. Specifically, the unrepeatable evolutionary history of each species makes it difficult to predict whether a given scenario would result in the same evolutionary outcome if it occurred more than once. One way around this problem is to exploit systems in which parallel evolution has occurred, because it is possible to distinguish the repeated effects of deterministic forces from those that differ due to stochastic processes. Pursuing these questions requires comparisons at both the intraspecific and interspecific level, using a variety of techniques including phylogeography, population genetics, and population genetics either at the level of individual loci or at a genomic scale.
My research involves the use of these approaches to examine the potential for and patterns resulting from parallel evolution in reference to both the origin of species and evolution within a lineage. My graduate work in the Rieseberg lab at Indiana University dealt with the origin and evolution of Helianthus deserticola, a wild sunflower species that likely has multiple independent origins.
In the Olsen lab, I am pursuing questions of selection and adaptation in cultivated and weedy rice, where parallel evolution has occurred due to artificial selection. There are two projects that I am working on:
- I am involved in the NSF weedy rice project going on in the lab. This project will help us understand the origin of weedy rice (or red rice) in the USA, as well the genetic basis and evolutionary dynamics of adaptive traits in this invasive plant.
- For my NIH postdoctoral fellowship, I am comparing the evolution domestication-related genes in Asian and African domesticated rice (Oryza sativa and O. glaberrima, respectively).
In the future, I am interested in focusing more specifically on the evolution of cultivated rice and the reproductive isolating barriers among species of rice, both wild and domesticated.
Here, I am standing in a field of rice that was replanted with soybeans (Arkansas, USA). It is likely that this field was replanted with soybeans because the rice crop was badly contaminated with weedy rice.