"Self Organization of Complex Patterns: A Biologic Case Study on How a Feather is Made"

10/26/2001: [time not recorded]
[location not recorded]

Abstract: How are complex patterns produced in biological and non-biological world? How are the information for the process stored and processed? Here we use the feather as a case study to summarize what we know about the rules of morphogenesis. Feathers comprise one of the most complicated and sophisticated epithelial organs as demonstrated by their shape, size, patterned arrangement, pigmentation, etc. Feathers are not made in one step. Many variations can occur at each of these levels leading to highly complex forms and function. Feathers are progressively patterned during development. The steps include 1) formation of tract fields on the integument surface of the bird, 2) Self organization into periodic arrangement of individual feather primordia within the feather tract, 3) setting up anterior - posterior and proximal - distal axes within a feather primordia, 4) branching morphogenesis of the rachis, barbs and barbules within a feather filament, and 5) additional global processes that produce gradients of variations of morphological parameters or pigmentation across a feather vane or across a whole feather tract. The breaking of symmetry from the original homogeneous feather primordia initiates the beginning of the making of a feather. Continuous building of multiple levels of asymmetry leads to the complex epithelial appendages we see as feathers. My laboratory has been working on identifying cellular and molecular mechanisms behind the process. As we try to decipher the processes behind many complex patterning existing in the physical world and learn to build complex patterns by genetic engineering and bio-technology, we can certainly learn from this biological case study on the rules of how a feather is built and how the many modulatable morphogenetic process can be used to store a lot of information and provide endless variations in complex pattern formation. It is certainly beneficial for biologists and engineers to learn and appreciate the logic and approaches of each discipline on how to generate complex patterns.

About Cheng-Ming Chuong: Dr. Cheng-Ming Chuong graduated with a M.D. from Nation of Taiwan University in 1978. He then received his Ph.D. in Developmental and Molecular Biology with Nobel Prize Laureate, Dr. Gerry M. Edelman in Rockefeller University in 1983. He moved to the University of Southern California in 1987 to set up the Laboratory of Tissues Development and Engineering. He is now a Professor of Pathology at University of Southern California. Dr. Chuong's research has been focused on developmental biology, the knowledge that study how a fertilized egg can develop into a well formed baby, not a tumor mass. He has been focusing to understand the molecular basis and rules used in tissue interactions for the formation of organs, or to examine and analyze the "language" used by the embryo to organize cells into organs. One of the major and unique models used in the laboratory is chicken feather morphgenesis. Using it, they study how the simple epithelial stem cells can generate the most complex patterns. They also studied other epithelial organs including liver, mammary gland, hair, teeth, etc. The goal is to understand fundamental principles of development on the basic side, and to use this knowledge on guiding stem cells for tissue engineering purposes on the application side. Taking a multi-discipline approaches, he also has developed collaborations with paleontologists to search for the origin and evolution of feathers in dinosaurs, and with computer scientists to decipher bio-information stored in biological cells. During these researches, Dr. Chuong's lab also spun out biotechnological inventions including Single Cell CDNA library (patented), RNA Polymerase Chain Reaction (patent pending), DRNA inteference, and other novel technologies which have applications in cancer and many other diseases. Dr. Chuong is the head of the Tissue Development Engineering Laboratory in Pathology, USC. The laboratory has two faculty (Dr. Wideliez and Dr. Jiang), and more than 15 members with different training background including molecular biology, developmental biology, evolution biology, dermatology, and surgery. Dr. Chuong has approximately 100 publications and one book, "Molecular Basis of Epithelial Appendage Morphogenesis". He is an international leader of his field, and has spoken in and organized many international symposia. He also serves as editors and reviewers for many academic journals, and serve as a reviewer for grant agencies including NIH. His laboratory has been supported by the National Institute of Health, National Science Foundation, and California Breast Cancer Research Program.

Last updated: Mon Jun 19 17:44:06 2006