In one embodiment, a polymerase chain reaction (PCR) system includes a mixture chamber, a denature chamber, an annealing chamber, an extension chamber, and a product chamber, that are fluidically coupled to one another through a plurality of microfluidic channels. An inertial pump is associated with each microfluidic channel, and each inertial pump includes a fluid actuator integrated asymmetrically within its associated microfluidic channel. The fluid actuators are capable of selective activation to circulate fluid between the chambers in a controlled cycle.