Information Isometry Technique Reveals Organizational Features in Developmental Cell Lineages
Lineage trees of embryonic development contain much subtle information about the embryogenetic process. One type of information is contained in how the order of nodes are sorted at each level of the tree. Sorting of lineage trees is accomplished using a specific criterion for all levels (each representing a division event) of the tree, resulting in new types of trees (e.g. differentiation tree). Another type of information can be revealed from pairwise comparisons of each type of tree. By using a binary classifier to quantify the first type of information (ordering by level), we can obtain a quantitative measure for the second type of information by using the Hamming distance between equivalent positions in two trees. In this paper, we will introduce a method for calculating and visualizing the information content of embryogenesis called the information isometry technique. Information is extracted from developmental lineages using a binary classification system, and visualization is accomplished through the construction of isometric graphs, which re-represent a tree topology as a series of isometric lines. As the points representing each segment of an isometric line changes color, there is a shift in the underlying tree and its constituent cells. Isometric graphs reveal a number of patterns within cell lineages, including the relative information content of specific subtrees.