Gene clusters representing differential transcription in ISE6 cells v. blood. The normalized expression values for the genes included in Clusters 2 (A), 1 (B) and 3 (C) as defined by K-means clustering are shown on the y axis. The x axis represents the two conditions in which the A. marginale were grown, bovine blood and tick cell culture. Each gene is represented by a line of unique color. Cluster 4, with a single gene down regulated in cell culture is not shown.