  Cell functional diversity is a significant determinant on how biological
processes unfold. Most accounts of diversity involve a search for sequence or
expression differences. Perhaps there are more subtle mechanisms at work. Using
the metaphor of information processing and decision-making might provide a
clearer view of these subtleties. Understanding adaptive and transformative
processes (such as cellular reprogramming) as a series of simple decisions
allows us to use a technique called cellular signal detection theory (cellular
SDT) to detect potential bias in mechanisms that favor one outcome over
another. We can apply method of detecting cellular reprogramming bias to
cellular reprogramming and other complex molecular processes. To demonstrate
scope of this method, we will critically examine differences between cell
phenotypes reprogrammed to muscle fiber and neuron phenotypes. In cases where
the signature of phenotypic bias is cryptic, signatures of genomic bias
(pre-existing and induced) may provide an alternative. The examination of these
alternates will be explored using data from a series of fibroblast cell lines
before cellular reprogramming (pre-existing) and differences between fractions
of cellular RNA for individual genes after drug treatment (induced). In
conclusion, the usefulness and limitations of this method and associated
analogies will be discussed.
