Ph.D. 2005, Columbia University New York
Phylogenetics and Biogeography
My research covers a broad range of topics related to evolution and genetics, primarily using birds as the subject. To date, these subjects include molecular evolution, phylogenetics, biogeography, diversification, patterns of diversity, and conservation. In terms of evolutionary genetics, my research scope includes divergences within species groups to the entire class Aves, utilizing both genomic-scale data and ancient/historical DNA techniques. My two main research programs involve deciphering the deep branches of the avian tree of life and using genetic data to examine species-limits and diversification across tropical Asia. Additional interests focus on issues of biogeography, particularly the geography of speciation, and biodiversity conservation. In my lab, we use DNA sequence data to reconstruct evolutionary history. We also compare the genetic signal to other aspects such as morphological characters to examine the correlation of genotype and phenotype as well as species ranges to examine gene flow, distributional patterns, and the potential impact of the various geological and climatic changes on diversification.
The Avian Tree of Life:
The diversification of birds is postulated to have occurred very rapidly, with the modern orders originating at roughly similar times. This pattern of radiation has led to enormous difficulty deciphering deep avian relationships. Our approach is to assemble a large genomic dataset to analyze the phylogeny of this diverse radiation (Hackett et al. 2008; Harshman et al. 2008; Kimball et al. 2009; Han et al. 2010).
Phylogenetics and Biogeography of Babblers (Timallidae):
The avifauna of southern Asia is one of the most diverse in the world, with tremendous species richness and endemism. Yet, despite some early interest from avian taxonomists and biogeographers, the Asian tropics have been the focus of relatively little modern systematic study. My studies show that genetic information is vital to untangle the confusion caused by traditional taxonomy of Asian birds, which underestimates species diversity more than four-fold (see Reddy and Cracraft 2007; Reddy 2008).
Biogeography and Biodiversity Conservation:
Biogeographic theory and practical studies have mostly focused on island systems, while less emphasis has been placed on examining the accumulation of species on continental systems. I am particularly interested in patterns of diversity and diversification across continental regions (see Reddy and Davalos 2003; Reddy 2005; Raxworthy et al. 2008; Reddy and Cracraft, 2007).
Kimball, R.T., E.L. Braun, F.K. Barker, R.C.K. Bowie, M.J. Braun, J.L. Chojnowski, S.J. Hackett, K.-L Han, J. Harshman, V. Heimer-Torres, W. Holznagel, C.J. Huddleston, B.D. Marks, K.J. Miglia, W.S. Moore, S. Reddy, F.H. Sheldon, J.V. Smith, C.C. Witt, and T. Yuri. In Press. A well-tested set of primers to amplify regions spread across the avian genome. Molecular Phylogenetics and Evolution.
Han, K-L, E.L. Braun, R.T. Kimball, S. Reddy, R.C.K. Bowie, M.J. Braun, J.L. Chojnowski, S.J. Hackett, J. Harshman, C.J. Huddleston, B.D. Marks, K.J. Miglia, W.S. Moore, F.H. Sheldon, D.W. Steadman, C.C. Witt, and T.Yuri. In Press. Are Transposons Homoplasy Free? An Examination Using the Avian Tree of Life. Systematic Biology.
Voelker, G, R.K. Outlaw, S. Reddy, M. Tobler, J.M. Bates, S.J. Hackett, C. Kahindo, B.D. Marks, J. Kerbis Peterhans, and T.P. Gnoske. 2010. A new species of black boubou from the Albertine Rift (Passeriformes: Laniidae: Laniarius). Auk 127: 678-689. ()
Kimball, R.T., E.L. Braun, F.K. Barker, R.C.K. Bowie, M.J. Braun, J.L. Chojnowski, S.J. Hackett, K.-L Han, J. Harshman, V. Heimer-Torres, W. Holznagel, C.J. Huddleston, B.D. Marks, K.J. Miglia, W.S. Moore, S. Reddy, F.H. Sheldon, J.V. Smith, C.C. Witt, and T. Yuri. 2009. A well-tested set of primers to amplify regions spread across the avian genome. Molecular Phylogenetics and Evolution 50: 654-660.
Hackett, S.J.*, R.T. Kimball*, S. Reddy*, R.C.K. Bowie, E.L. Braun, M.J. Braun, J.L. Chojnowski, W.A. Cox, K. Han, J. Harshman, C.J. Huddleston, B.D. Marks, K.J. Miglia, W.S. Moore, F.H. Sheldon, D.W. Steadman, C.C. Witt, T. Yuri. 2008. A phylogenomic study of birds reveals their evolutionary history. Science 320: 1763-1768. *These authors contributed equally to the manuscript and were listed alphabetically.
Reddy, S. 2008. Systematics and biogeography of the shrike-babblers (Pteruthius): species limits, molecular phylogenetics, and diversification patterns across southern Asia. Molecular Phylogenetics and Evolution 47: 54–72. ()
Harshman J., E.L. Braun, M.J. Braun, C.J. Huddleston, R.C.K. Bowie, J.L. Chojnowski, S. Hackett, K-L. Han, R.T. Kimball, B.D. Marks, K.J. Miglia, W.A. Moore, S. Reddy, F.H. Sheldon, D.W. Steadman, S.J. Steppan, C. Witt, and T. Yuri. 2008. Phylogenomic evidence for multiple losses of flight in ratite birds. Proceedings of National Academy of Sciences 105: 13462-13467. ()
Raxworthy, C.J., R.G. Pearson, B.M. Zimkus, S. Reddy, A.J. Deo, R.A. Nussbaum, and C.M. Ingram. 2008. Continental speciation in the tropics: contrasting biogeographic patterns of divergence in the Uroplatus leaf-tailed gecko radiation of Madagascar. Journal of Zoology 275: 423-440. ()
Reddy, S. and J. Cracraft. 2007. Old World Shrike-babblers (Pteruthius) belong with New World Vireos (Vireonidae). Molecular Phylogenetics and Evolution 44: 1352–1357. ()
Reddy, S. and L.M. Davalos. 2003. Geographical sampling bias and its implications for conservation priorities in Africa. Journal of Biogeography 30: 1719-1727. ()