Fig. 3
Clustering analysis of the candidate reference genes expression. (A) Heatmap of hierarchical cluster analysis of samples performed on the profiles of 21 candidate reference genes to depict the similarity of gene profiles; (B) Supervised Orthogonal partial least squared-discriminant (OPLS-DA) score plot. Three phases can be distinguished in the gene expression features, that are (1) embryo stage, (2) first 7Â days after birth, (3) 1 to 9Â months after birth