  We present a stochastic framework to study signal transmission in a generic
two-step cascade $\text{S} \rightarrow \text{X} \rightarrow \text{Y}$. Starting
from a set of Langevin equations obeying Gaussian noise processes we calculate
the variance and covariance while considering both linear and nonlinear
production terms for different biochemical species of the cascade. These
quantities are then used to calculate the net synergy within the purview of
partial information decomposition. We show that redundancy in information
transmission is essentially an important consequence of Markovian property of
the two-step cascade motif. We also show that redundancy increases fidelity of
the signalling pathway.

Molecular Networks