Hierarchal clustering by gene and developmental stage. Four clusters of up-regulated genes were identified: 1, Aquatic/snail stages; 2 and 3, Adult female worms; 4. Adult male worms. Gene expression is shown in the heat map as up-regulated (Red) down-regulated (Green) or no change (Black). E, eggs; M, miracidia; S, sporocysts; C, cercariae; L, lung schistosomula; F4, juvenile females; M4, juvenile males; F6, F6.5, F7, adult female worms analysed at 6, 6.5 and 7 weeks post-cercarial challenge; M6, M6.5, M7, adult male worms analysed at 6, 6.5 and 7 weeks post-cercarial challenge.