[philgoetz]

It is extremely unlikely that the brain encodes information by introducing controlled mutations into DNA. Random mutations would add noise, not information.

It is likely that some mutations affect the efficiency of signal propagation, and encoding might adapt to this, so that equivalent inputs would create more or fewer or "stronger" or "weaker" synapses to generate the same output from the second neuron. But this could be detected functionally, if you could observe the signals and responses of neuron pairs.