Table 2. The seven negative control sets included in the meta-analysis.

Data set	Description	Number of genes	Reference, species and microarray chip
Suai_mm	Differentiated tissue–42 tissue types	256	Su et al 2002 [21] (mouse;mgu74a)
Ivanova_MBC_mgu74av2_2	Mature Blood Cells	224	Ivanova et al 2002 [18] (mouse; mgu74av2)
Random_mgu74av2_2	∼10% of chip sampled	1250	Generated in this study (mouse; mgu74av2)
Random_mgu74av2_15P1	∼15% of chip sampled	1900
Random_mgu74av2_15P2	∼15% of chip sampled	1900
Random_mgu74av2_15P3	∼15% of chip sampled	1899
Baek_mm	Transcripts with promoters categorized (mouse)	4189	Baek et al 2007 [15] (mouse;na)

The key to abbreviation: na - not applicable.