| NSF Org: |
DEB Division Of Environmental Biology |
| Recipient: |
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| Initial Amendment Date: | May 7, 2013 |
| Latest Amendment Date: | May 7, 2013 |
| Award Number: | 1311269 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Samuel Scheiner
DEB Division Of Environmental Biology BIO Directorate for Biological Sciences |
| Start Date: | May 15, 2013 |
| End Date: | April 30, 2016 (Estimated) |
| Total Intended Award Amount: | $20,404.00 |
| Total Awarded Amount to Date: | $20,404.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
2200 W MAIN ST DURHAM NC US 27705-4640 (919)684-3030 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Durham NC US 27705-4010 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | EVOLUTIONARY GENETICS |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.074 |
ABSTRACT
Despite the prevalence of sexual reproduction in nature, asexual reproduction is also found in many diverse organisms. Apomixis (asexual reproduction via clonal seed) occurs in approximately 400 genera across 40 different plant families, and is always associated with polyploidy (whole genome duplication) and hybridization. To date, these confounding factors have prevented investigation of the evolutionary and ecological processes maintaining apomixis in plant populations. The genus Boechera, a self-fertilizing wild relative of Arabidopsis thaliana, contains diploid apomicts. This offers a unique opportunity to disentangle the factors underlying apomixis and polyploidy. The proposed research examines the processes underlying a sexual/apomictic breeding system polymorphism in wild populations of Boechera, using population genetic models that historically are designed for diploid organisms. Understanding the link between apomixis and hybridization still remains problematic. Any putative fitness effects of apomixis may be due to hybridization, which introduces genetic variation to inbred Boechera. Through a combination of crossing experiments, field research, and genomic sequencing techniques, the PIs will investigate the fitness effects of hybridization and increased genetic diversity in Boechera. This research permits complete separation of these two confounding factors from the study of apomixis for the first time.
Most crops are of hybrid origin, and the introduction of apomixis promises fixation of advantageous lineages through their clonal offspring; therefore, apomixis is of great agricultural interest. A developed understanding of the evolutionary maintenance of this breeding system in nature is critical to current and future efforts to battle hunger across the world. Training of students will occur.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
In July 2015, Catherine Rushworth completed research for her dissertation “Evolutionary and ecological factors maintaining apomixis in Boechera, a wild relative of Arabidopsis” supported by an NSF Doctoral Dissertation Improvement Grant.
Rushworth is an evolutionary biologist interested in the maintenance of reproductive variation in natural environments. The specific form of reproduction she focuses on is apomixis, a naturally occurring form of asexual reproduction in which the seeds produced are clonal copies of the parent plant. Apomixis has arisen independently in nearly 20% of angiosperm families, suggesting evolutionary importance. Additionally, apomixis is of great interest to the agricultural science community, offering promise for fixation of high-yield crop lineages. Yet nearly nothing is known about how apomixis arises and is maintained in natural populations. It is crucially important to obtain an understanding of these processes prior to the development of genetically modified apomictic crops.
During her funding period, Rushworth spent several months of each year studying her focal plant Boechera in its natural environment. To understand the patterns of natural selection that maintain reproductive variation, she planted thousands of plants that she identified as reproducing sexually or asexually into experimental garden sites in the Rocky Mountains. Because apomixis is associated with increased genetic heterozygosity (the presence of multiple alleles at a genetic locus) in numerous plant species, she also conducted experiments to understand how this factor might influence the maintenance of apomixis. These additional projects were funded by an NSF Doctoral Dissertation Improvement Grant. Cumulatively, she found that apomictic Boechera have higher survival than their sexual counterparts, although they experience much higher insect herbivory. Increased survival is also seen in outcrossed plants that have higher heterozygosity, which suggests that survival in apomicts may be associated with heterozygosity. Currently the precise mechanisms for these differences are unknown, which provides future directions for Rushworth’s research.
Rushworth participated in numerous outreach activities during completion of this research, including mentoring young women and girls in science through Girl Scouts of America and the regional program Women And Mathematics. She also mentored multiple undergraduate researchers, working for several years with two female minority undergraduate students. Both of these students have since moved on to postgraduate work, one in medicine and one in biology. While funded by the NSF, Rushworth also applied her undergraduate degree in public relations and management toward the development and teaching of two professional development courses for graduate students. Scientists receive little to no training in management and mentorship, yet are expected to lead teams of researchers for the duration of their careers. By linking her undergraduate and now graduate degrees, Rushworth plans to continue addressing management issues in biological research during her career.
Last Modified: 05/25/2016
Modified by: Catherine Rushworth
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