Distinguished Research Professor
Ph.D. (1986) Australian National University
  • Visiting Professorship, National Center for Biological Sciences, Tata Institute of Fundamental Research – (Bengaluru, India)
  • Named a Distinguished Research Professor, University of Georgia
  • Fellow, American Association for the Advancement of Science
  • "Thousand Talents" Awardee (Chinese Academy of Sciences)
  • Visiting Professorship, Dipartimento di Biologia Vegetale, Università di Roma 'La Sapienza', Rome, Italy
  • Visiting Research Fellowship, Merton College, University of Oxford (Trinity Term 2007)
  • Visiting Professorship, Universitat Autònoma de Barcelona, Barcelona, Spain, 2005
  • Visiting Professorship, Universität Konstanz, Konstanz Germany, 2004
  • Creative Research Medal, University of Georgia, 1997
  • Distinguished Merit Award, Society for Louisiana Irises
  • Research Interests -
    • Members of Mike Arnold’s lab have tested evolutionary hypotheses in a wide array of organisms – including fungi, plants and animals.  In spite of the taxonomic diversity reflected in this work, there is a unifying theme.  This theme is well described by the title of a 1954 Evolution paper authored by the plant evolutionary biologists, Edgar Anderson and Ledyard Stebbins – “Hybridization as an Evolutionary Stimulus”.  Thus, our group has examined a range of phenomena associated with the process of gene exchange between organisms in nature.  The data collected have derived from analyses of population genetics, phylogenetics, reproductive biology, pollinator behavior, eco-physiology, molecular evolution and, most recently, linkage/QTL mapping of fitness traits.
Research Area: 
Selected Publications: 


  • Arnold, M.L. 2015. Divergence With Genetic Exchange. Oxford University Press. In press.
  • Arnold, M.L. 2009. Reticulate Evolution and Humans – Origins and Ecology. Oxford University Press.
  • Arnold, M.L. 2006. Evolution Through Genetic Exchange. Oxford University Press.
  • Arnold, M.L. 1997. Natural Hybridization and Evolution. Oxford Series in Ecology and Evolution, Oxford University Press.

Reseach papers, reviews and book chapters:

  • Arnold, M.L., A.N. Brothers, J.A.P. Hamlin, S.J. Taylor and N.H. Martin. 2015. Divergence-with-gene-flow – What humans and other mammals got up to. In press.
  • Hamlin, J.A.P. and M.L. Arnold. 2014. Determining population structure and hybridization for two Louisiana Iris species. Ecology and Evolution 4:743-755.
  • Arnold, M.L. 2014. Hybrid Speciation. In Oxford Bibliographies Online: Evolutionary Biology, http://www.oxfordbibliographies.com/view/document/obo-9780199941728/obo-.... J.B. Losos ed. Oxford University Press, New York.
  • Ballerini, E.S., K. Mockaitis and M.L. Arnold. 2013. Transcriptome sequencing and phylogenetic analysis of Type II MIKCC MADS-box and R2R3 MYB transcription factors in reproductive tissue from the non-grass monocot Iris fulva. Gene 531:337-346.
  • Brothers, A.N., J.G. Barb, E.S. Ballerini, D.W. Drury, S.J. Knapp and M.L. Arnold. 2013. The genetic architecture of floral traits in Iris hexagona and Iris fulva. Journal of Heredity 104:853-861.
  • Arnold, M.L., J.A.P. Hamlin, A.N. Brothers and E.S. Ballerini. 2012. Natural hybridization as a catalyst of rapid evolutionary change. Chapter 25, Pp. 256-265. In Rapidly evolving genes and genetic systems, R.S. Singh, J. Xu, and R.J. Kulathinal eds. Oxford University Press, Oxford.
  • Ballerini, E.S., A.N. Brothers, S. Tang, S.J. Knapp, A. Bouck, S.J. Taylor, M.L. Arnold and N.H. Martin. 2012. QTL mapping reveals the genetic architecture of loci affecting pre- and post-zygotic isolating barriers in Louisiana Iris. BMC Plant Biology 12:91.
  • Arnold, M.L., E.S. Ballerini and A.N. Brothers. 2012. Hybrid fitness, adaptation and evolutionary diversification: lessons learned from Louisiana Irises. Heredity 108: 159-166.
  • Dobson, M.C., S.J. Taylor, M.L. Arnold and N.H. Martin. 2011. Patterns of herbivory and fungal infection in experimental Louisiana Iris hybrids. Evolutionary Ecology Research 13: 543-552.
  • Liu, J., L. Yu, M.L. Arnold, C-H. Wu, S-F. Wu, X. Lu and Y-P. Zhang. 2011. Reticulate evolution: frequent introgressive hybridization of Chinese hares (genus Lepus) revealed by analyses of multiple mitochondrial and nuclear DNA sequences. BMC Evolutionary Biology 11: 223.
  • Arnold, M.L. (ed). 2010. Reticulate Evolution. Genes.
  • Arnold, M.L. and N.H. Martin. 2010. Hybrid fitness across time and habitats. Trends in Ecology and Evolution 25: 530-536.
  • Arnold, M.L., S. Tang, S.J. Knapp and N.H. Martin. 2010. Asymmetric introgressive hybridization among Louisiana Iris species. Genes 1: 9-22.
  • Tang, S., R.A. Okashah,  S.J. Knapp, M.L. Arnold and N.H. Martin. 2010. Reproductive isolation in Louisiana irises: Transmission ratio distortion. BMC Plant Biology 10: 48.
  • Taylor, S.J., M.L. Arnold and N.H. Martin. 2009. The genetic architecture of reproductive isolation in Louisiana Irises: Hybrid fitness in nature. Evolution 63: 2581-2594.
  • Zinner, D., M.L. Arnold and C. Roos. 2009. Is the new primate genus Rungwecebus a baboon? PLoS ONE 4: e4859.
  • Martin, N.H., Y. Sapir and M.L. Arnold. 2008. The genetic architecture of reproductive isolation in Louisiana Irises: Pollination syndromes and pollinator preferences. Evolution 62: 740-752.
  • Arnold, M.L. 2008. Reticulate Evolution and Humans – Origins and Ecology. Oxford University Press.
  • Cornman, R.S. and M.L. Arnold. 2007. Phylogeography of Iris missouriensis (Iridaceae) using transposon display. Molecular Ecology 16: 4585-4598.
  • Martin, N.H., A.C. Bouck and M.L. Arnold. 2006. Detecting adaptive trait introgression between Iris fulva and I. brevicaulis in highly selective field conditions. Genetics 172: 2481-2489.
  • Bouck, A.C., R. Peeler, M.L. Arnold and S.R. Wessler. 2005. Genetic mapping of species boundaries in Louisiana Irises using IRRE retrotransposon display markers. Genetics 171: 1289-1303.
  • Cornman, R.S., J.M. Burke, R.A. Wesselingh and M.L. Arnold. 2004. Contrasting genetic structure of adults and progeny in a Louisiana Iris hybrid population. Evolution 58: 2669-2681.
  • Johnston, J.A., L.A. Donovan and M.L. Arnold. 2004. Novel phenotypes among early generation hybrids of two Louisiana Iris species: Flooding experiments. Journal of Ecology 92: 967-976.
  • Kentner, E.K., M.L. Arnold and S.R. Wessler. 2003. Characterization of high copy number retrotransposons from the large genomes of the Louisiana Iris species and their use as molecular markers. Genetics 164: 685-697.
  • Burke, J.M., M.R. Bulger, R.A. Wesselingh and M.L. Arnold. 2000. Frequency and spatial patterning of clonal reproduction in Louisiana Iris hybrid populations. Evolution 54: 137-144.
Research Interests Detail: 

Hybridization and evolution: process of gene exchange between organisms in nature; hybridization as an evolutionary stimulus

Spotlight text: 

Divergence with Genetic Exchange
Mike’s new book is an investigation into processes associated with evolutionary divergence and diversification.  The focus, as the title indicates, is on the role played by the exchange of genes between divergent lineages.  This process has been given various names with one of the most recent being “divergence-with-gene-flow.” Examples of genetic exchange-mediated evolution include organisms from all domains of life.  Though the mechanisms by which such divergent forms of life exchange genomic material differ widely, the outcomes of interest – i.e. adaptive evolution and the formation of new “hybrid” lineages – do not.  The various chapter and section divisions thus reflect the history, methodologies for detecting, outcomes, implications for conservation programs and the effects on the human lineage associated with the process of genetic transfer between divergent lineages.