  Recently, it has been shown that the holomorphic anomaly of unitarity cuts
can be used as a tool in determining the one-loop amplitudes in N=4 super
Yang-Mills theory. It is interesting to examine whether this method can be
applied to more general cases. We present results for a non-MHV N=1
supersymmetric one-loop amplitude. We show that the holomorphic anomaly of each
unitarity cut correctly reproduces the action on the amplitude's imaginary part
of the differential operators corresponding to collinearity in twistor space.
We find that the use of the holomorphic anomaly to evaluate the amplitude
requires the solution of differential rather than algebraic equations.
