Our next Friday Seminar speaker is Professor Elena Kramer, Harvard University.
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The lower eudicot model system Aquilegia possesses several morphological features that can shed light on the evolution of novelty, particularly in the context of complex organ form.
We have been studying two key aspects of the Aquilegia flower: the three-dimensional petal nectar spur and a fifth floral organ type, the staminode. In the case of the petal spur, we have found that Aquilegia petal spurs initiate due to a localised region of cell division.
This lays the ground pattern of the spur, which is then realised through rapid, anisotropic cell elongation that is the major determinant of spur length and curvature. Diversification of spur morphology has involved multiple factors, including heterochronic shifts that generate much longer, narrower cells; differences in cell numbers around the radial axis of the spur; and independent control of cell elongation on different surfaces of the spur, which generates curvature.
We are now combining transcriptomics, candidate gene approaches, and QTL mapping to explore the genetic architecture of spur development and understand its evolution.
In the case of the staminode, we have previously discovered that this novel organ identity is determined via the combinatorial activity of paralogs of the genes that normally confer stamen identity, such that the stamens and staminodes now have distinct genetic codes via sub- and neofunctionalisation.
We are further exploring the developmental and morphological oddities of the staminodes, what their ecological function may be, and how their developmental program diverges from that of stamens.
Time permitting, I will also discuss a new research direction in the lab relating to the developmental and genetic basis of floral meristem termination in Aquilegia. This work combines candidate gene and QTL approaches with live imaging to investigate the coordination of floral organ identity and floral meristem termination in this model with multiple whorls of stamens
Professor Elena Kramer biography
Elena Kramer attended Brandeis University, where she conducted research with Dr Jeffrey C. Hall on the courtship mutant cacophony in Drosophila melanogaster.
For her PhD, she worked with Dr. Vivian Irish in the Dept. of Biology at Yale University, studying the evolution of the APETALA3 and PISTILLATA gene lineages, which generally control petal and stamen identity in angiosperms.
After a brief postdoctoral appointment with Gunter Wagner, also at Yale, she joined the faculty of the Dept. of Organismic and Evolutionary Biology at Harvard Univ. in 2000. She was promoted to tenure in 2007 and named the Bussey Professor of Organismic and Evolutionary Biology in 2012.
She is currently serving as Chair of the Department of Organismic and Evolutionary Biology, and the Interim Director of the Harvard University Herbaria.
Elena’s lab studies the evolution of genetic programs controlling flower development, particularly in the lower eudicot Aquilegia (columbine). Their work includes gene lineage evolution, comparative gene expression, functional studies, transcriptomics, evolutionary genetics & genomics, and even a little ecology.
She is particularly interested in the genetic basis of morphological novelties, like the petal spur and staminodes of Aquilegia.