Avian integument provides multiple possibilities to analyse different phases of skin appendage morphogenesis.

To analyse the morphogenic events during skin appendage formation, it is important to have an animal model that offers distinct patterns at various stages of development and is accessible to analysis using state of the art technology. The avian integument is such a model. Combining experimental embryologic approaches, organ cultures, and gene transduction technology, we are now able to begin to address the molecular basis of pattern formation, primordium initiation, anterior-posterior axis formation, proximo-distal axis formation, phenotypic determination, and others. Parallel mechanisms are usually found in feathers and hairs, and the avian integument model has matured to be a major source of new findings in the study of skin appendage morphogenesis. More information on the avian integument model can be found at website http://www.hsc.usc.educmchuong.