  In order to function reliably, synthetic molecular circuits require
mechanisms that allow them to adapt to environmental disturbances. Least mean
squares (LMS) schemes, such as commonly encountered in signal processing and
control, provide a powerful means to accomplish that goal. In this paper we
show how the traditional LMS algorithm can be implemented at the molecular
level using only a few elementary biomolecular reactions. We demonstrate our
approach using several simulation studies and discuss its relevance to
synthetic biology.
