Microarrays of the MWG 14k Zebrafish Oligonucleotide Set were produced using the facilities of the Leiden Genome Technology Center (http://www.lgtc.nl). Oligonucleotides were dissolved in 150mM phosphate buffer (pH 8.5) to a concentration of 20 µM. With Omnigrid 100 (Genemachines) oligonucleotides were spotted on Codelink activated slides (Amersham Biosciences) according to the Amersham Codelink protocol and as described in (‘t Hoen et al 2003 and Meijer et al 2004). Microarrays were spotted according to the MIAME guidelines with 15.532 unique zebrafish oligonucleotides from the MWG oligonucleotide set. Ambion’s arraycontrol oligonucleotides (8 sense oligos) and 3 custom designed oligonucleotides were spotted together with the MWG oligonucleotide set. Spotted Codelink activated slides were treated with blocking solution and washed according to the manufacturer’s instructions.