Gene expression in chicken embryo liver

We have profiled the gene expression in eight chicken embryo livers in the 11th day of incubation. Four eggs (labelled as WAT1-4) were injected with 0.15 ml/egg deionized water in days 9, 10 an 11 post incubation while four eggs (labeled CTR1-4) were kept as environmental controls. We found that water injections had a very small effect, regulating less than 1% of the genes. Both WAT and CTR data sets were used as references in further experiments for eggs expossed to various water-soluble carcinogenic compounds. Differently labelled biological replicas were co-hybridized with the same microarray. Expression of genes in similarly labeled samples of the two conditions were compared and the results averaged.