Hopf bifurcation analysis for a model of genetic regulatory system with delay

This paper deals with a mathematical model that describe a genetic regulatory system. The model has a delay which affects the dynamics of the system. We investigate the stability switches when the delay varies, and show that Hopf bifurcations may occur within certain range of the model parameters. By combining the normal form method with the center manifold theorem, we are able to determine the direction of the bifurcation and the stability of the bifurcated periodic solutions. Finally, some numerical simulations are carried out to support the analytic results.