Figure 4: (a) Representative immunoblotting analysis of sperm from CD1 (top panel) and B6 (bottom panel) strain of mice, indicating band intensity obtained for PLCζ and a-tubulin. Images are representative of 3 × 3 repeats from each strain of mouse, for each age group. (b) Linear regression model constructed using normalized relatively density of PLCζ in relation to age, regardless of strain. A statistically significant negative correlation can be observed (Pearson's correlation coefficient [r] = −0.9995; r = 0.9991) with advancing male age. (c) Representative histogram indicating the relative density observed in sperm from B6 and CD1 mice in relation to advancing male age.*Statistically significant differences (P ≤ 0.05). NS: not significant. Comparisons made are indicated by the respective line above the bars. B6: C57BL/6 inbred mouse strain; CD1: outbred mouse strain; PLCζ: phospholipase C zeta.