One hundred seventy-four miRNAs meeting threshold criteria (ANOVA FDR <5%,
test for multiple comparisons (
< 0.05), and fold change ≥1.5) for differential expression by age or sex were included in principal component analysis. Each sphere represents the expression profile of one animal plotted in three-dimensional space according to the top three principal components. Spheres of the same color are animals of the same age group (weeks of age). Spheres with black vertices indicated females while those without represent males (n = 4 or 5).