Fig. 3.
A Bayesian Network representing a hypothetical gene-regulation pathway. This structure of a hypothetical Bayesian Network contains five nodes. The probabilities associated with this network structure are not shown. The network structure indicates that Gene1 can regulate (influence) the expression level of Gene3, which in turn can regulate the expression level of Gene5. The Markov condition gives the conditional independence relationships that are specified by a Bayesian Network: A node is independent of its non-descendants (e.g., non-effects) given its parents (i.e., its direct influences).