Walter M. FitchProfessor, Ecology & Evolutionary Biology |
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Research Interests |
Molecular Evolution | |
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Research Abstract |
Molecular evolutionary studies can shed much light on a vast array of interesting biological problems. My research is eclectic, and tries to answer any and all of these problems to the extent that the sequence information in proteins and/or nucleic acids is available and the methods are suitable. To perform such studies one must detect significant similarity among sequences, align them homologously, and infer ancestral relationships and sequences. I spend a considerable amount of time inventing new and improving old ways of accomplishing such tasks. I am especially interested currently in ways of assigning weights to different nucleotide positions so that one may have greater confidence in the resulting phylogeny (evolutionary tree). An associated problem is how to allow for the fact that some amino acids may not be allowed to vary among insects but are variable among vertebrates and vice versa. The best part of research is when a new improvement permits one to see new things. New things we've seen recently include the following: 1. An analysis of 350 isoaccepting tRNA's for eight amino acids from all the kingdoms showed that the various isoacceptors evolved by gene duplications that occurred prior to the most recent common ancestor of everything that is alive today. It also showed that the pattern of gene duplications follows the pattern of the genetic code as if the earliest duplications separated recognition of purines from pyrimidines and later duplications separated recognition of A from G and C from U. This is a progression that suggests the genetic code was originally ambiguous and that the gene duplications arose so as to permit an increasingly refined specification of the amino acid to be encoded. Thus we appear to be recognizing evolutionary processes that occurred 3.5 billion years ago. 2. An analysis of the genes of the influenza virus isolated from 1933 to the present has permitted us to study the evolution of flu where the "fossils" are accurately dated. The rate of evolution for the hemagglutinin gene turns out to be as fast as for any known gene, 10-2 substitutions/site/year with a rate so constant that I can determine the year of the virus' isolation if given the sequence. Moreover, we were able to prove that this enormous rate is associated with positive Darwinian selection where the coat of the virus is changing rapidly, the benefit being the change in the viral antigenic sites. This confers a temporary escape of the virus from immune surveillance. Thus we appear to be recognizing evolutionary processes that occurred in the last few decades. |
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| Publications | Fitch, W.M. and Margoliash, E. 1967. The construction of phylogenetic trees - a generally applicable method utilizing estimates of the mutation distance obtained from cytochrome c sequences. Science 155: 279-284. | |
| Fitch, W.M. 1971. Toward defining the course of evolution: minimum change for a specific tree topology. Systematic Zoology 20: 406-416. | ||
| Fitch, W. M. 1977. Trees and Crossovers, Genetics, 86: 623-644. | ||
| Fitch, W.M. and Atchley, W.R. 1985. Evolution in inbred strains of mice appears rapid. Science 228: 1169-1175. | ||
| Fitch, W.M. and Upper, K. 1988. The phylogeny of tRNA sequences provides evidence for ambiguity reduction in the origin of the genetic code. Cold Spring Harbor Symposium on Quantitative Biology. 52: 759-767. | ||
| Williams, P.L. and Fitch, W.F., Phylogeny Determination Using a Dynamically-Weighted Parsimony Method. Methods in Enzymology, 183, 615-625 (1990). | ||
| Atchley, William R. and Fitch, Walter M., Gene Trees and the Origins of Inbred Strains of Mice. Science, 254, 554-558 (1991). | ||
| Fitch, W.M., Leiter, J.M.E., Li, X. and Palese, P., Positive Darwinian Evolution in Human Influenza A Viruses. Proc. Nat. Acad. Sci., 88, 4270-4274 (1991). | ||
| Rudikoff, S., Fitch, W.M. and Heller, M., Exon-specific Gene Correction (conversion) during Short Evolutionary Periods: Homogenization in a Two-Gene Family Encod ing the ( Chain Constant Region of the T-Lymphocyte Antigen Receptor. Mol. Biol. Evol. 9, 14-26 (1992). | ||
| Fitch, W.M., Peterson, E.M. and de la Maza, L.M., Phylogenetic Analysis of the Outer Membrane Protein Genes of Chlamydiae and its Implication for Vaccine Developm ent. Mol. Biol. Evol. 10, 892-913 (1993). | ||
| Nichol, S.T., Rowe, J.E. and Fitch, W.M., Punctuated Equilibrium and Positive Darwinian Evolution in Vesicular Stomatitis Virus. Proc. Nat. Acad. Sci. 90, 10424- 10428 (1993). | ||
| Atchley, William R. and Fitch, Walter M., Genetic Affinities among Inbred Strains of Laboratory Mice. Mol. Biol. Evol. 10, 1150-1169 (1993). | ||
| Fitch, W.M. and Ayala, F.J., The Superoxide Dismutase Molecular Clock Revisited. Proc. Nat'l. Acad. Sci. (USA) 91, 6802-6807 (1994). | ||
| Xu, Shizhong, Atchley, William R. and Fitch, Walter M. Phylogenetic Inference Under the Pure Drift Model. Mol. Biol. Evol. 6, 949-960 (1994). | ||
| Atchley, William R., Fitch, Walter M. and Bronner-Fraser, Marianne. Molecular Evolution of the MyoD Family of Transcription Factors. Proc. Nat. Acad. Sci (USA) 91, 11522-11526 (1994). | ||
| Miyamoto, Michael M. and Fitch, Walter M. Testing the Covarion Hypothesis of Molecular Evolution. Mol. Biol. Evol. 12, 503-513 (1995). | ||
| Fitch, Walter M. Uses for Evolutionary Trees. Phil. Trans. Royal Society LondonB) 349, 93-102 (1995). | ||
| Atchley, William R. and Fitch, Walter M. Myc and Max: Molecular Evolution of a Family of Proto-Oncogenes and their Dimerization Partner. Proc. Nat. Acad. Sci. 92, 10217-10221 (1995). | ||
| Atchley, William R. and Fitch, Walter M. A Natural Classification of the Helix-Loop-Helix Class of Transcription Factors. Proc. Nat. Acad. Sci. 94, 5172-5176 (1997). | ||
| Fitch, Walter M., Bush, Robin M., Bender Catherine A. and Cox, Nancy J. Long term trends in the evolution of H(3) HA1 human influenza type A. Proc. Nat. Acad. Sci. 94, 7712-7718 (1997). | ||
| Finkelstein, Mark, Fitch, Walter M., Lanciani, Carmine A. and Miyamoto, Michael M. Estimating the Probabilities of Runs of Identical Events within Biological Sequences. Mol. Biol. & Evol. 15, 470-472 (1998). | ||
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Rodriguez,
Luis L., Fitch, Walter M. and Nichol, Stuart. Ecological factors
rather than temporal factors dominate the evolution of vesicular
stomatitis virus. Proc. Nat. Acad. Sci. 93:13030-13035. |
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Bush,
Robin M., Fitch, Walter M., Bender, Catherine A. and Cox, Nancy
J. Positive Selection on the H3 Hemagglutinin Gene of Human Influenza
Virus A, Mol. Biol. and Evol, 16, 1457-1465 (1999). |
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Bush,
Robin M., Bender, Catherine A., Subbarao, Kanta Cox, Nancy J, and
Fitch, Walter M. Predicting the Evolution of Human Influenza A,
Science, 286:1921-1925 (1999). |
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Atchley,
William. R., Wollenberg, K. R., Fitch, Walter M., Terhalle, Werner,
and Dress, Andreas W. Correlations among amino acid sites in bHLH
protein domains: An information theoretic analysis. Molecular Biology
and Evolution, 17: 164-178 (2000). |
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Fitch,
Walter M. Homology: a personal view on some of the problems. Trends
in Genetics, 16: 227-231 (2000). |
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Fitch,
Walter M., Bush, Robin M., Bender, Catherine A. Subbarao, Kanta
and Cox, Nancy J. On Predicting the evolution of human influenza
A, Journal of Heredity, 91(3): 183-185 (2000). |
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| Bush, Robin M., Smith, Catherine A., Subbarao, Kanta, Fitch, Walter M. and Cox, Nancy J. Effects of passage history and sampling bias on phylogenetic reconstruction of human influenza A evolution. Proceedings of the National Academy of Sciences (US), 97 (13): 6974-6980 (2000). | ||
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Evolution of the hemagglutinin of Type B Human Influenza Virus Walter M. Fitch and Geoff Graham |
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Professional Societies |
National Academy of Sciences
American Association for the Advancement of Science
American Chemical Society
The Biochemical Society (British) (lapsed)
American Society for Biochemistry and Molecular Biology
Genetics Society of America
Society of Systematic Biology
Society for the Study of Evolution American Academy of Arts and Sciences Society for Mathematical Biology National Academy of Sciences (U.S.) American Academy of Arts and Sciences (U.S.) Human Genome Organization Society for Molecular Biology and Evolution Linnean Society (London) |
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| Link to this profile | http://www.faculty.uci.edu/profile.cfm?faculty_id=2117 | |
| Last updated | 07/05/2007 | |