Tail length analysis in comet assay with sperm from mice with NPYq deficiencies - ANOVA analysis. (a) An increase in comet tail length due to sperm freezing in controls (P = 0.000001) and NPYq deficient mice (P = 0.0084). (b) An increase in comet tail length with testicular as compared to epididymal sperm in controls (P = 0.001) but not in NPYq deficient mice. (c) Comparison of NPYq deficient genotypes with their respective controls showing the significant increase in comet tail length in 9/10NPYq- (P = 0.0093) and NPYq-2 (P = 0.0036). Two males were used per genotype; four sperm groups (epididymal, frozen epididymal, testicular and frozen testicular) were examined per male; 100 sperm were scored per group per male.