Unusual features of the urodele genome: do they have a role in evolution and development?

Urodeles are amongst the organisms with the highest C-values. They provide a useful system for studies of genome organization at both the chromosomal and the molecular level. In this contribution we discuss the general features of "excess" DNA in urodeles and emphasize that the urodele genome is in a state of plasticity. That fluidity is due to various molecular mechanisms which are involved in its continuous turnover. The implications of this fluid, "excess DNA" for evolution and/or development are considered.