Research Interests

I use molecular genetic markers to investigate the evolutionary history of organisms, populations and higher taxa. My studies span a diversity of biological systems and topics, conceptually unified by a phylogenetic perspective based on molecular phylogenies. All forms of life share a common history due to the transmission of hereditary material over eons and generations, and this history may be traced back in time through analysis of genetic lineages. The distribution of gene genealogies in time and space is a manifestation of current and historical processes that operate at diverse levels in the hierarchy of life. Molecular genetic data may be used to study biological processes as ancient as the origin of the main forms of life and as recent as a familiar pedigree.

From macro- to microevolutionary processes, my research involves the study of adaptive radiations such as the ancient diversification of major taxa, biogeographic distributions, coevolution, geographic population structure, gene flow, and mating patterns. Most of my work has been focused on vertebrate animals, and predominantly on fishes, but I have recently started to apply the same approach to host-parasite systems and to assess patterns of vertical transmission of HIV.

Recent Publications

• H. Zhang, G. Orti, Q. Du, J. He, C. Kankasa, G. Bhat, and C. Wood 2002. Phylogenetic and phenotypic analysis of HIV-1 Env gp120 in cases of subtype C mother to child transmission. AIDS Res. Hum. Retrov. 18:1415-1423.
• Brant, S.V. and G. Ort. 2002. A molecular phylogeny of short-tailed shrews, Blarina (Insectivora: Soricidae). Molecular Phylogenetics and Evolution (22): 163-173
• Farias, I.P., G. Ort, I. Sampaio, H. Schneider, and A. Meyer. 2001. The cytochrome b gene as a phylogenetic marker: the limits of resolution for analyzing relationships among cichlid fishes. Journal of Molecular Evolution 53: 89-103
• Sivasundar, A., E. Bermingham, and G. Ort. 2001. Population structure and biogeography of migratory freshwater fishes (Prochilodus: Characiformes) in major South American rivers. Molecular Ecology 10(2): 407-418.
• Huang, Y., G. Ort, M. Sutherlin, A. Duhachek, and A. Zera. 2000. Phylogenetic relationships of North American field crickets inferred from mitochondrial DNA data. Molecular Phylogenetics and Evolution 17(1): 48-57.
• Farias, I.P., G. Ort, and A. Meyer. 2000. Total evidence: molecules, morphology and the phylogenetics of cichlid fishes. J. Exp. Zool. (Mol. Dev. Evol.) 288(1): 76-92.
• Farias, I.P., G. Ort, I. Sampaio, H. Schneider, and A. Meyer. 1999. Mitochondrial DNA phylogeny of the family cichlidae: monophyly and high rate of molecular evolution of the Neotropical assemblage. Journal of Molecular Evolution 48:703-711
• Walker, D., G. Ort, and J.C. Avise. 1998. Phylogenetic distinctiveness of a threatened aquatic turtle (Sternotherus depressus). Conservation Biology 12:639-645
• Ort, G., D.E. Pearse, and J.C. Avise. 1997. Phylogenetic assessment of length variation at a microsatellite locus. Proc. Natl. Acad. Sci. USA 94:10745-10749.
• Ort, G, M.P. Hare, and J.C. Avise. 1997. Detection and isolation of nuclear haplotypes by PCR-SSCP. Molecular Ecology 6: 575-580.