  In this paper, we describe the context sensitivity problem encountered in
partitioning a heterogeneous biological sequence into statistically homogeneous
segments. After showing signatures of the problem in the bacterial genomes of
Escherichia coli K-12 MG1655 and Pseudomonas syringae DC3000, when these are
segmented using two entropic segmentation schemes, we clarify the contextual
origins of these signatures through mean-field analyses of the segmentation
schemes. Finally, we explain why we believe all sequence segmentation schems
are plagued by the context sensitivity problem.
