Conservation of gene expression levels between human and mouse platelets or between human platelets and PMNs. (A-B) Scatter plots comparing the RPKMs of human platelet genes (x-axis) plotted against the RPKM (y-axis) of the corresponding gene in mouse platelets (A) or in human PMNs (B). Only genes with a human-mouse ortholog are represented. (C-D) The RPKM cutoff used in a Spearman rank correlation analysis (x-axis), plotted against the corresponding value of the ρ correlation coefficient calculated when comparing (C) human and mouse platelets or (D) human platelets and human PMNs. For example, the y-value of the far left point (0 RPKM) represents the ρ correlation coefficient between the RPKMs of all genes expressed in either sample. The y-value of the point at 0.3 RPKM on the x-axis (the vertical line) represents the ρ correlation coefficient calculated for all genes with an RPKM > 0.3 in both samples. The far right point includes only the 20 most highly expressed genes in the calculation of the corresponding correlation coefficient. (E-F) Scatter plots comparing, after removal of all ubiquitously expressed genes, the RPKMs of human platelet genes (x-axis) versus the RPKM of the corresponding gene (y-axis) in mouse platelets (E) or in human PMNs (F). (G-H) After removal of all ubiquitously expressed genes, the RPKM cutoff used in a Spearman rank correlation analysis (x-axis) is plotted against the corresponding value of the ρ correlation coefficient (y-axis) calculated comparing (G) human and mouse platelets or (H) human platelets and human PMNs. All plots shown represent samples isolated via Trizol.