(1) The identification of genes that are transcriptionally regulated in response to exposure to hypoxia (~0.2% oxygen) in H99 (WT) and strains CM092 and CM098. (2) The identification of genes that are differentially-regulated in the strain CM093 compared to H99 (WT) Keywords: hypoxia response, comparative transcriptional hybridization 8 cultures for each strain (4 grown in normoxia and 4 grown in hypoxia) are analyzed on 4 microarrays for each strain (normoxia hybridized against hypoxia). Two out of four microarrays contain dye-swaps.