Each of these four tracks shows the binding sites for STAT1 ChIP-chip using Human Hela S3 cells hybridized to four different array designs/platforms. The first three platforms are custom maskless photolithographic arrays with oligonucleotides tiling most of the non-repetitive DNA sequence of the ENCODE regions:
The fourth array platform is an ENCODE PCR Amplicon array manufactured by Bing Ren's lab at UCSD.
Each track shows the combined results of multiple biological replicates: five for the first maskless array (50-mer every 38 bp), two for the second maskless array (36-mer every 36 bp), three for the third maskless array (50-mer every 50 bp) and six for the PCR Amplicon array. For all arrays, the STAT1 ChIP DNA was labeled with Cy5 and the control DNA was labeled with Cy3. See NCBI GEO GSE2714 for details of the experimental protocols.