Figure 5From: Selection of reference genes for quantitative real-time PCR in equine in vivo and fresh and frozen-thawed in vitro blastocystsDetermination of the optimal number of control genes for normalization. The optimal number of control genes for normalization was calculated by geNorm. The value of the pairwise variations reduces until 0.207 for V3/4, which indicates that the inclusion a fourth reference gene contributes to the stability. Therefore the average of the 4 most stable genes is recommended to determine a reliable NF.Back to article page