Strain: C57BL6 Embryo E18, Male/Female total RNA (MoEm.MF18) received from National Human Genome Research Institute was analyzed through Bioanalyzer and passed our quality control test. The mRNA was processed according to the MPSS protocol as outlined in the previous publications (Brenner, S., et al. (2000) Proc Natl Acad Sci U S A 97(4): 1665-1670 and Brenner, S. et al., Nat. Biotechnol 18(6): 630-634). Briefly, the mRNA was reverse transcribed and the cDNA was digested with Dpn II. The 20 bases adjacent to the 3? most Dpn II site was cloned into a Megaclone vector. The resulting library was amplified and loaded onto microbeads. About 1.6 million microbeads were loaded into each flow cell and the signature sequences were determined by a series of enzymatic reactions as outlined in the above publications. The abundance for each signature was converted to transcripts per million (tpm) for the purpose of comparisons between samples. Cells/tissue: Library MoEm.MF18.sig21 Cell type Embryo E18, Male/Female Source NHGRI RNA isolation LYNX mRNA QC passed cDNA library: Library DpnII restriction - (signature cloning using MmeI) Sequence length 20 bp MPSS: runs MoEm.MF18_sig21.5323W.a-20 1/17/2005 588926 13280 QC Passed MoEm.MF18_sig21.5323W.b-20 1/17/2005 541669 13473 QC Passed MoEm.MF18_sig21.5323F.a-20 1/15/2005 503235 12810 QC Passed MoEm.MF18_sig21.5210F.a-20 10/7/2004 436012 9384 QC Passed Run group: Total Beads successfully sequenced - 2069842 Processed Signatures - 18592