Figure 1

Correlation and hierarchical analyses of transcriptomes of bovine in vivo developed oocytes and embryos. (A). Heatmap of duplicate samples of the same stages of bovine embryonic development. The color spectrum, ranging from red through white to blue, represents Pearson correlation coefficients ranging from 1 to 0.53, indicating high to low correlations. All duplicate samples are highly correlated in Pearson coefficients demonstrating the reproducibility of the procedures. (B). Principal component analysis (PCA) of the transcriptomes for seven stages of in vivo developed bovine embryos and oocytes. Embryos from the same stage are shown by symbols of the same shape. The arrows indicate the developmental direction of the embryos. PC1, PC2 and PC3 represent the top three dimensions of the differentially expressed genes among the preimplantation embryos. (C). Hierarchical clustering of differentially expressed genes in in vivo developed bovine oocytes and embryos. Two major clusters are shown, one consisted of the matured oocytes and embryos at the 2- and 4-cell stages. The second cluster is consisted of embryos at the 8-, 16-cell, early morula, compact morula and blastocyst stages. The clear separation of embryos into two groups demonstrated the timing of EGA in cattle at the 4- to 8-cell transition. The color spectrum, ranging from red through yellow to blue, indicates normalized levels of gene expression. (D). The numbers of differentially expressed genes in consecutive stages of bovine in vivo pre-implantation development (P < 0.05).