Significantly developmentally expressed trypanosome genes grouped by functional class. Genes represented by array oligonucleotides were grouped by function, based on sequence similarity to annotated sequences, domain annotation, GO terms and additional criteria. The proportion in each functional class significantly upregulated in BSF are shown in red and in PCF in green. The remaining fraction of genes in each class are shown in grey. The first bar illustrates the proportion of developmentally regulated transcripts in the entire studied gene cohort. For raw data [see Additional file 6].