New type of turbulence, or how symmetry results in chaos

Pattern formation and transition to chaos in a macroscopic dissipative syst em is discussed. It is supposed that the system has a continuous family of spatially uniform states, which can be transformed into each other by a cer tain symmetry transformation. If such a system undergoes instability agains t spatially periodic perturbations with a finite wavenumber, interplay of s hort-wavelength modes associated with the instability and long-wavelengths modes generated by the symmetry transformation affects the dynamics of the system dramatically. In particular, it may result in direct transition from a spatially uniform state to spatiotemporal chaos, analogous to second ord er phase transition in equilibrium systems. The obtained results may be app lied to kinetic of polymerization, to reaction-diffusion problems, to flame propagation, to some hydrodynamic problems, etc.