Table 4.

Expressed genes and transcripts in developing mouse tissues and cultured stem cells

	EM	PL	ES	TS	Any tissue	All tissues
mRNAs/cell	851,087	519,688	400,045	568,196
Features ≥ 1 CpC	13,718	10,559	9,667	9,840	14,908	8,073
U-clusters ≥ 1 CpC	11,360	8,828	8,101	8,271	12,264	6,838
Transcripts ≥ 1 CpC	11,762	9,108	8,357	8,534	12,739	7,037
Mean copies per cell	1.09	0.63	0.51	0.56
Median copies per cell	0.79	0.45	0.36	0.40

U-clusters and transcripts from the NIA mouse gene index were considered expressed if microarray features measured absolute expression estimated at one copy per cell or more. Copy-number estimates from expressed transcripts were summed to estimate the number of mRNA molecules per cell for each tissue, as well as the mean and median copy numbers. Microarray features corresponding to expressed genes and transcripts were mapped to the NIA Gene Index to calculate the number of U-clusters (loci) and transcripts expressed in each tissue.