Figure 5. Analysis of blood and immune cell type-specific genes across evolution reveals evidence for hematopoietic precursors in B. schlosseri.
We analyzed gene expression microarray data from 26 different human blood cell populations, organized into four cell lineages (HSC; Lymphoid Progenitors; Myeloid and Lymphoid Lineage), and identified a set of twenty signature genes with highly enriched expression profiles for each population (Supplementary file 3). For each blood-related gene set, we identified homologous gene sequences in B. schlosseri and 17 other species; the fraction of genes (out of 20) found for each species is displayed as a heat map. Within each major lineage, cell populations are sorted in decreasing order by a conservation index, calculated as the average number of genes found across the 18 species (indicated by a blue bar graph).