Over time, the position of a gene in its genome often changes, but the functional consequences of such gene movements are largely unknown. To help fill this gap, these three investigators are not only exploiting the wealth of research tools and resources available for the model plant Arabidopsis, along with the genome sequences for papaya, grape, and poplar, they are also creating new ones. Focusing on Arabidopsis's 26,500 non-transposon, non-tandem genes, and using a new top-down, multi-alignment algorithm to infer gene order in the last common ancestor of Arabidopsis and papaya, grape, and poplar, the investigators have found evidence for an ancient hexaploidy shared by all dicots and perhaps all plants. Additional preliminary data show that about 40% of Arabidopsis genes are no longer ancestral, either because they (1) have diverged rapidly; (2) exhibit a high birth-and-death behavior in the phylogenetic tree; (3) are positioned in rearrangement-prone regions of the chromosome; or (4) have transposed to new locations in the genome. Interestingly, a "flanking gene test" has shown that certain gene families contain genes that are almost always newly transposed. The investigators also show that conserved noncoding sequences sometimes subfunctionalize among homeologs. Over 4,000 deeply conserved noncoding sequences (CNSs) are shared between papaya and Arabidopsis. These regulatory sites will be sorted to gene, made into a database, and evaluated for subfunctionalization at the level of sequence, gene expression, and fitness (reproductive output) through the use of knockout mutations and phenotypic analyses. In addition, using microarray data normalized by The Arabidopsis Information Resource (TAIR), the investigators will test, in silico, hypotheses concerning issues such as the relationship between genes' positions and their coregulation.
Broader Impacts of Project. This project provides exciting training opportunities at both pre- and postgraduate levels. The investigators will continue their long-established partnerships with Chevron on the SEED project, and with Berkeley High School on improving biology training for promising, underserved minority high school students. The Freeling laboratory provides these students with paid summer research experiences tailored to the needs of the students and their families. The University of Georgia ranks sixth in the US in percentage of minorities, and research there is closely tied to strong outreach programs. This project will contribute to the development and implementation of research-based educational materials to improve comprehension and mastery of scientific concepts by middle and high school students through training of one teacher per year in the GIFT (Georgia Internships for Teachers) program. Together with GIFT, the investigators seek to nucleate a "teachers-teach-teachers" program that uses metaphorical examples and dialogue to portray key scientific concepts without becoming ensnarled in the debate on creationism, an issue prominent in many areas, including Georgia and South Carolina. In addition, exchanges between the three institutions will enhance the scientific and cultural experiences of these investigators students and add further to the bonds formed by research collaboration. The investigators on this project will communicate with the public and provide data and applications for download at their NSF 2010 project-specific website, www.plantgenome.uga.edu/outgroup.html .
