A Snapshot of My Research
On any given day, I am mentoring students, planting seeds, repotting plants, collecting leaf tissue, extracting DNA, doing PCR, preparing tissues for microscopy, planning field trips, and writing manuscripts.
The pictures in this slide show is a compilation of the places and people with whom I work. Greenhouse culture is a large part of my research. I have had full greenhouse genetic experiments under my supervision since 2007: first ~600 Draba, then ~900 Tragopogon, and then ~600 Solanum. Prior to 2007, I either assisted in the culture of soybean, corn, or Arabidopsis, and a permeant plant systematics collection during teaching Botany lab. Before my plant science career flourished, I was a professionally trained landscape and production horticulturalist.
I also have been traveling to the various regions within the North American Cordillera for the past five summers to collect more Draba species. My colleagues and I bring leaves and seeds back from the wild for molecular work. My background in chemistry makes me an extremely unique botanist who really knows the way around the lab.
Herbaria are also a large part of my research as many specimens in my datasets are taken directly from vouchers as well as depositing new ones from my own field work.
My Current Study Systems
Genome Changes in Polyploidy
During my post-doctorate with the Soltis Lab, I joined Team Trag where I was part of a large effort to develop the genus into an excellent model system to study natural formation and genome behavior of allopolyploids.
My role in Team Trag was to carry out a large scale study proposed by Richard Buggs, that investigates the expression and gene loss or gain changes from one generation of allopolyploids to the next. This experiment involved the use of multiple natural populations from the distribution of the natural diploids and naturally occurring allotetraploids, in combination with three different generations of synthetically produced tetraploid lines.
This experiment had a massive greenhouse and growth chamber design that is leading to excellent findings regarding gene loss or gain in the process of polyploidization. Using modern techniques, Team Trag obtained NGS (Next Generation Sequencing) results from 454 and Illumina to develop primers for this large gene expression study, that ultimately was done with a PCR-based, Mass Spectrometry Genotyping method, Sequenom. Additionally, we measured various physiological and growth aspects of the plants to identify any differences among them. The results are under analysis, so keep an eye out!
Phylogeny, phylogeography, alpine adpatation, polyploidy and apomixis
My PhD work with Prof. Dr. Marcus A. Koch and Dr. Ihsan Al-Shehbaz, was focused on the biodiversity and molecular systematics of Draba L. I have continued to work with this genus and plan to continue.
There are more than 96 Draba species found within the North American Cordillera, and 56 of them are found just within the Central Rocky Mountains (and ~400 Draba worldwide).
Draba oligopserma Hook, few-seeded whitlow grass, has an unusual distribution for Draba, having the widest distribution in mid- to high altitudes from Alaska to Arizona, and from California to Wyoming. Preliminary results indicate it might be an allopolyploid, and that it is definitely an apomict, which we have shown with flow cytometry of seeds and exploration of embryogenesis. However, Mulligan, a notable Canadian botanist, proposed there might be sexual populations, but are yet to be identified.
I am investigating the population genetics, and related species in hopes of understanding the role of speciation and apomixis to adaptation in this genus. I am determining true population sizes for Draba oligosperma from Alberta, California, Idaho, Montana, Nevada, Utah, Wyoming, and Yukon. I hope to understand the genetic flow within and between populations to detect the possibility of historical sexual events.
Phylogeography and Dioecy
My most recent post-doctoral work with Dr. Chris Martine at Bucknell University is on the phylogenetics, population genomics, and phylogeography of Australian dioecious Solanum spp. (Solanaceae). We are working to understand the species complex found in northern Australia. Our research uses phylogenomics, population genomics, classical genetic crosses, and microscopy to investigate the role of functional dioecy in the speciation of this genus and its populations.
We grew ~600 plants of two species of Solanum (S. asymetriphyllum and S. sejunctum), and begun a long term study on these closely related species. There are functionally dioecious (separate male and female plants), and hermaphroditic plants. We have observed a rather frequent occurrence of the male plants reverting to hermaphrodites within their inflorescence.
We also have been able to create a hybrid between the two species and are undergoing genetic and chromosomal studies of this artifical hybrid. Dr. Martine has observed plants int he wild that might be naturally occurring hybrids between these two species. We will work on dating the divergence of these two species with our population genomic work using ddRADtag and targeted genomic sequencing, as well as understanding their migration and population structure.
Additionally, we have four other species complexes that we are investigating with population genomics. Our goal is to understand the historical biogeography of this species complex.
The functionally dioecious flowers have also been a new area of investigation. Our microscopic observations have identified the stages of "failure" for both the development of the gametophytes (pollen and the ovules) in the different sexes.