  A distributed computing system is a collection of processors that communicate
either by reading and writing from a shared memory or by sending messages over
some communication network. Most prior biologically inspired distributed
computing algorithms rely on message passing as the communication model. Here
we show that in the process of genome-wide epigenetic modifications cells
utilize their DNA as a shared memory system. We formulate a particular
consensus problem, called the epigenetic consensus problem, that cells attempt
to solve using this shared memory model, and then present algorithms, derive
expected run time and discuss, analyze and simulate improved methods for
solving this problem. Analysis of real biological data indicates that the
computational methods indeed reflect aspects of the biological process for
genome-wide epigenetic modifications.
