Species-specific probes of pair-wise human and mouse homologous housekeeping genes. The expression of 26 species specific probes (SSPs) corresponding to 13 pairs of human and mouse homologous housekeeping genes (HK) are shown according to two experimental conditions: exposure to the H&M array to Human RNA (X axis) or mouse RNA (Y axis). Each point is the mean expression value of 3 arrays and the whiskers are the 95% confidential intervals (n = 6 arrays total). A median fold change for the 13 pairs of SSPs resulted in a 10.4 fold change for human SSPs (panel A) and 9.7 fold change for mouse SSPs (panel B). Homologous genes utilised: RNASEH1, PMPCB, SFRS8, PRDX6, TRAPPC4, MATR3, NIPA2, MRPL49, NOL7, VPS26A, HNRPDL, RPL39, OSBP.