Comparison of DNA Sequence of H3 (Histone) and Centromere H3 (Cen H3) in Memebers of the Gossypium (Cotton) Genus Gene McClugage, Ryan Rapp, Jonathan Wendel and EEOB at Iowa State University ABSTRACT The goal of this research was to analyze the Histone3(H3) gene sequence of the members of the Gossypium genus and the Centromere H3 (CenH3). In comparing these two sets of genes sequences we wanted to determine the evolutionary rate of change as each species diverged from the parent species for the CenH3. This also will verify or improve upon the phylogenetic relationships currently accepted. This research then sets the groundwork for understanding the mechanisms that led to the diversification of CenH3 in the various Gossypium species. RESEARCH QUESTION How different or similar are the Cen H3 sequences between the various species of Gossypium genus when using the Histone H3 as a baseline comparison? METHODS PCR Amplification Cloning using an E. coli strain Plasmid Prep (DNA Extraction) Sequencing of DNA (Plasmid) Analysis ACKNOWLEDGEMENTS I would like to thank the Plant Genomics Outreach Program including Adah Leshem-Ackerman and Jonathan Wendel for the opportunity to participate in the RET program. I would especially like to thank Ryan Rapp and Ryan Percifield for their mentoring, patience and willingness to put up with me in the lab. I would also like to thank the Biotechnology Outreach Education Center and the Office of Biotechnology as well as the NSF for funding this program. RESULTS Cloning technigues successful. Plasmid isolation successful Sequencing not so successful. Second time sequencing not successful. Third time sequencing not successful. Problem solve. Try again. Keep fingers crossed. BACKGROUND The centromeres (CenH3) protein of the different Gossypium species as well as many other species has shown quick evolutionary change. In comparison the Histone H3 shows very little change over time between the different species. The H3 binds approximately 120 bp as does the CenH3. The centromere H3 is a key protein of the centromere that participates in the binding of the chromosome to the spindle fibers during mitosis or meiosis. DISCUSSION Arabidopsis has both the H3 Histone and Centromeric H3 protein complex. It was found that the centromeric H3 proteins of Arabidopsis. thaliana and A. arenosa showed remarkable adaptive evolution. Suggesting the same mechanisms for selection pressure in the species. In Gossypium species it would then be assumed that the same pattern should be exhibited when the similar centromeric H3 complex and Histone H3 complex is analyzed. This logic would also be supported by the recent and rapid diversification of the Gossypium genus. At this point in the research there is no definitive answer as to whether or not Cen H3 shows significant diversity among the various species of Gossypium. REFERENCES Charles T. Bryson, USDA Agricultural Research, Bugwood.org Cronn R.C., Small, R. L. Haselkorn, Tamara, Wendel, J.F. (2002) Rapid Diversification of the Cotton Genus (Gossypium: Malvaceae) Revealed By Analysis of Sixteen Nuclear and Chloroplast Genes. American Journal of Botany 89(4), Talbert, Paul B. Masuelli Ricardo, Tyagi Anand P. Comai, Lucas and Steven Henikoff (May 2002) Centromeric Localization and Adaptive Evolution of an Arabidopsis Histone H3 Variant. The Plant Cell 14,