Dan Sloan

Graduate Student

Plant mitochondrial genomes are exceptional within the eukaryotic world. In particular, their size, structural organization and mutational properties set them apart from other mitochondrial genomes. Investigating the evolutionary forces that have shaped plant mitochondrial genomes is an important step towards understanding their functional biology. For example, the origin and maintenance of “selfish” genetic elements that give rise to widespread cytoplasmic male sterility in flowering plants are of great interest in both agriculture and evolutionary theory. Moreover, the divergent evolutionary history of mitochondrial genomes offers a valuable model to address the broader question of how genomes and genomic complexity evolve.

In the last decade, research on plant mitochondrial genomes has revealed spectacular patterns of mutation rate variation at multiple biological scales. In our studies of the genus Silene, we have found that mitochondrial mutation rates vary dramatically among genes, among species and among lineages within species. In extreme cases, inferred mutation rates differ by more than 100-fold between closely-related species. What are the effects of evolving under a high vs. low mutation rate? My ongoing dissertation research examines the genomic and population genetic consequences of mutation rate variation in plant mitochondria to address this overarching question.

Related publications

• Sloan DB, Oxelman B, Rautenberg A, Taylor DR. 2009. Phylogenetic analysis of mitochondrial substitution rate variation in the angiosperm tribe Sileneae. BMC Evolutionary Biology. 9:260. pdf
• Sloan DB, Barr CM, Olson, MS, Keller SR, Taylor DR. 2008. Evolutionary rate variation at multiple levels of biological organization in plant mitochondrial DNA. Molecular Biology and Evolution. 25(2): 243-246. pdf
• Barr CM, Keller SR, Ingvarsson PK, Sloan DB, Taylor DR. 2007. Variation in polymorphism and mutation rate among mitochondrial genes in Silene vulgaris. Molecular Biology and Evolution. 24(8): 1783-1791. pdf

Publications from ongoing side projects and ghosts of research past

• Sloan DB, Panjeti VG. In Press. Evolutionary feedbacks between reproductive mode and mutation rate exacerbate the paradox of sex. Evolution. pdf
• Sloan DB, Giraud T, Hood ME. 2008. Maximized virulence in a sterilizing pathogen: the anther-smut fungus and its co-evolved hosts. Journal of Evolutionary Biology. 21(6): 1544-1554. pdf
• Bret-Harte MS, Mack MC, Goldsmith GR, Sloan DB, DeMarco J, Shaver GR, Ray PM, Biesinger Z, Chapin FS III. 2008. Plant functional types do not predict biomass responses to removal and fertilization in Alaskan tussock tundra. Journal of Ecology. 76:713-726. pdf
• Pillitteri LJ, Sloan DB, Bogenschutz NL, Torii KU. 2007. Termination of asymmetric cell division and differentiation of stomata. Nature. 445: 501-505. pdf
• Antonovics JA, Abbate JL, Baker CH, Daley D, Hood ME, Jenkins C, Johnson LJ, Murray JJ, Panjeti V, Rudolf VHW, Sloan DB, Vondrasek J. 2007. Evolution by any other name: Antibiotic resistance and avoidance of the E-word. PLoS Biology. 5(2): e30. pdf
• McCormick MK, Whigham DF, Sloan DB, O'Malley K, Hodkinson B. 2006. Orchid-fungal fidelity: a marriage meant to last? Ecology. 87(4): 903-911. pdf
• Heschel MS, Sultan SE, Glover S, and Sloan DB. 2004. Population differentiation and plastic responses to drought stress in the generalist annual, Polygonum persicaria. Int. J. Plant Sci. 165(5): 817-824. pdf

---