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Roger H. Sawyer Senior Associate Dean of Natural Sciences, |
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Roger H. Sawyer Senior Associate Dean of Natural Sciences, |
It is known that tissue interactions regulate developmental events such as cell proliferation, cell movement and cell adhesion. These events are under the regulation of cell adhesion molecules, substrate adhesion molecules and their receptors. Such receptors provide the linkage for signal transduction from extracellular matrix molecules to the controlling machinery of the cell or cell population. Using numerous immunological and molecular probes to these important molecules, Professor Sawyer is defining the steps involved in the morphogenesis, histogenesis and terminal differentiation of skin appendages. The ultimate goal of this research is to understand the biochemical and molecular basis of pattern formation of skin appendages. This will require an understanding of both the genetic and epigenetic regulatory mechanisms at work as development of these appendages takes place.
Sawyer, R.H., T.C. Glenn, J.O. French and L.W. Knapp. (2005) Developing Antibodies to Synthetic Peptides Based on Comparative DNA sequencing of Multigene Families. In Methods in Enzymology395, Molecular Evolution: Producing the Biochemical Data, Part B. E.A. Zimmer and E.H. Roalson (eds.), Academic Press, San Diego. pp. 636-651.
Sawyer, R.H., L. Rogers, L. Washington, T.C. Glenn and L.W. Knapp. (2005) The Evolutionary Origin of the Feather Epidermis. Developmental Dynamics. 232:256-267.
Alibardi, L., L.W. Knapp, and R.H. Sawyer. (2005) Development of down feathers in an altricial bird (Zebrafinch, Taeniopigia guttata): implications for the evolution of feathers. J. of Anat., in press.
Sawyer, R.H. and L.W. Knapp. (2003) Avian Skin Development and the Evolutionary origin of feathers. J. Exp. Zool. (Mol. Dev. Evol.) 298B:57-72.
Sawyer, R.H. Washington, L.D. Salvatore, B.A. Glenn, T.C. and L.W. Knapp. (2003) Origin of Archosaurian Integumentary Appendages: The Bristles of the Wild Turkey Beard Express Feather-Type ? Keratins. J. Exp. Zool. (Mol & Dev Evol) 297B: 27-34.
Sawyer, R.H., Salvatore, B.A., Potylicki, T-T. F., French, J.O., Glenn, T.C., and Knapp, L.K. (2003) Origin of Feathers: Feather Beta (?) Keratins are Expressed in Discrete Epidermal Cell Populations of embryonic Scutate Scales. J. Exp. Zool. (Mol. Dev. Evol) 295B: 12-24.
Sawyer, R.H. and L.W. Knapp. (2003) Embryonic Induction. In: Hall B.K., Olson W.M., eds. Keywords and concepts in evolutionary developmental biology. Harvard University Press. Cambridge, pp.102-108.
Davis, L.M., Glenn, T.C., Strickland, D.C., Guillette, L.J., Elsey, R.M., Rhodes, W.E., Dessauer, H.C., and R.H. Sawyer. (2002) Microsatellite DNA analyses support an east-west phylogeographic split of American Alligator populations. J. Exp. Zool. (Mol. Dev. Evol.) 294:352-372.
Glenn, T.C., Staton, J.L., Vu, A.T., Davis, L.M., Bremer, J.R., Rhodes, W.E., Brisbin, I.L., and R.H. Sawyer. (2002) Low mitochondrial DNA variation among American Alligators and a novel non-coding region in crocodilians. J. Exp. Zool. (Mol. Dev. Evol.) 294:312-324.
Alibardi L, Sawyer RH. 2002. Immunocytochemical analysis of beta keratin in the epidermis of chelonians, lepidosaurians and archosaurians. J. Exp. Zool. 293: 27-38.
Homer BL, Li C, Berry KH, Denslow ND, Jacobson ER, Sawyer RH, Williams JE. (2001) Soluble scute proteins of health and ill desert tortoises (Gopherus agassizii). Am. J Veterinary Res. 62:104-110.
Davis,L.M., Glenn,T.C., Elsey, R.M., Dessauer, H. R.H. Sawyer. (2001) Multiply Paternity and Mating Patterns in the American Alligator, Alligator mississippiensis. Molecular Ecology 10: 1011-1024.
Sawyer, R.H., Glenn, T.C., French, J.O., Mays, B., Shames, R.B., Barnes, G.L., Rhodes, W. and Y. Ishikawa. (2000) The Expression of Beta Keratins in the Epidermal Appendages of Reptiles and Birds. In: Symposium on the Origin of Feathers. Am. Zool., 40:530-539.
Davis, L. M., T. C. Glenn, R. M. Elsey, I. L. Brisbin Jr., W. E. Rhodes, H. C. Dessauer and R. H. Sawyer. (2000). Genetic structure of six populations of American alligators: A microsatellite analysis. Pages 38-50 In Crocodilian Biology and Evolution, (G. C. Grigg, F. Seebacher, and C. E. Franklin, eds.), Surrey Beatty and Sons. Australia.
Song, H.K. and R.H. Sawyer (1996) The dorsal dermis of the scaleless (sc/sc) embryo directs normal feather pattern formation until day 8 of development. Dev. Dynamics 205, 92-99.
Barnes, G.L. and R.H. Sawyer (1995) Histidine-rich protein B of embryonic feathers is present in the transient embryonic layers of scutate scales. J. Exp. Zool. 271, 307-314.
Shames, R.B., B.C. Bade, and R.H. Sawyer. (1994) Role of epidermal-dermal tissue interactions in regulating tenascin expression during development of the chick scutate scale. J. Exp. Zool. 269, 366-349.
Knapp, L.W., R.B. Shames, G.B. Barnes, and R.H. Sawyer. (1993) Region specific patterns of beta keratin expression during avian skin development. Dev. Dynamics 196, 283-290.
Song, H.K., W.E. Carver, and R.H. Sawyer. (1993) Pattern formation in chick feather development: distribution of B1-integrin in normal and scaleless embryos. Dev. Dynamics 200, 129-143.
Zeltinger, J.K. and R.H. Sawyer. (1992) Avian Scale Development XVII. The epidermis of the scaleless (sc/sc) anterior metatarsal skin is determined, but the dermis lacks permissive cues for the patterned expression of the determined state. Dev. Dynamics 193:58-69.
Zeltinger, J.K. and R.H. Sawyer. (1992) Avian Scale Development XVI. Epidermal commitment to terminal differentiation is prior to definitive scale ridge formation. Dev. Biol. 149:55-65.
Shames, R.B., A.G. Jennings and R.H. Sawyer. (1991) The initial expression and patterned appearance of tenascin in scutate scales is absent from the dermis of the scaleless (sc/sc) chicken. Dev. Biol. 147:174-186.