Heatmap, correlation analysis, and principal component analysis (PCA) for the follicle fluid (FF) samples based on quantification of the all identified proteins in yak. a Heatmap shows the global expression difference of the FF samples based on the total identified proteins. b Correlation matrix illustrates correlations among the yak FF samples of the mature and immature FF. c Scree plot exhibits the first six principal component of the PCA for the FF samples. d PCA biplot shows the first two principal components (Dim1 and Dim2). The correlation of each variable with each axis is indicated by the length and angle of lime segments. e Correlation matrix illustrates correlations between each yak FF sample and each principal component of the first five principal components.