Pathline is a visualization tool for comparative functional genomics that supports analysis of three types of biological data at once: functional data such as gene activity measurements; pathway data that presents a series of reactions within a cellular process; and phylogenetic data describing ancestral relationships between species.

The design of Pathline includes two new visual encoding techniques. The first is an encoding of a linearized metabolic pathway representation that provides appropriate topological information and supports the comparison of quantitative data along the pathway. The second is a curvemap, a matrix layout of temporal expression data for enhanced perception of trends in gene and cell activity levels across multiple species.