Table 2. Genes with differential expression in 2-cell embryos.

Exp. Group	2CE DE genes [n]	DE ratio>1 [n (%)]	DE ratio<1 [n (%)]
Parg(110)−/−(arrays)	1241	972(78.3)	269 (21.7)
Parg(110)−/− (NGS)	370	337 (91.1)	33 (8.9)
PJ34 inj. (arrays)	1095	869 (79.4)	225 (20.6)

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.