Genes with differential expression in 2-cell embryos.

Separating differentially expressed genes in 2-cell embryos (2CEDE) into up-regulated (ratio>1) and down-regulated genes (ratio<1) reveals a strong bias of differentially-expressed genes towards up-regulation or illegitimate activation of genes across all experimental groups/platforms used. The numbers in brackets indicate percentage of genes in a category, e.g., 75.4% of all genes detected in the microarrays of Parg(110)−/− 2CE DE were up-regulated and 24.6% were down-regulated.