TitlePositional information, in bits.
Publication TypeJournal Article
Year of Publication2013
AuthorsDubuis, JO, Tkačik, G, Wieschaus, EF, Gregor, T, Bialek, W
JournalProc Natl Acad Sci U S A
Volume110
Issue41
Pagination16301-8
Date Published2013 Oct 8
KeywordsAnimals, Cell Movement, Drosophila, Embryonic Development, Gene Expression Regulation, Developmental, Gene Regulatory Networks, Models, Biological, Proteins
Abstract

Cells in a developing embryo have no direct way of "measuring" their physical position. Through a variety of processes, however, the expression levels of multiple genes come to be correlated with position, and these expression levels thus form a code for "positional information." We show how to measure this information, in bits, using the gap genes in the Drosophila embryo as an example. Individual genes carry nearly two bits of information, twice as much as would be expected if the expression patterns consisted only of on/off domains separated by sharp boundaries. Taken together, four gap genes carry enough information to define a cell's location with an error bar of ~1 along the anterior/posterior axis of the embryo. This precision is nearly enough for each cell to have a unique identity, which is the maximum information the system can use, and is nearly constant along the length of the embryo. We argue that this constancy is a signature of optimality in the transmission of information from primary morphogen inputs to the output of the gap gene network.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.