Incidence of paternal chromosome breaks (aberration rate) in zygotes produced by ICSI with sperm from mice with NPYq deficiencies - ANOVA analysis. (a) An increase in chromosome aberration rate due to sperm freezing in controls (P = 0.025) and NPYq deficient mice (P < 0.000001). (b) Comparison of NPYq-deficient genotypes with their respective controls showing the significant increase in chromosome aberration rate in 9/10NPYq- (P = 0.000145) and NPYq-2 (P = 0.000019). (c) Genotype/sperm status interaction, showing that with increasing NPYq deficiency the increase in chromosome aberration rates is much more marked with frozen than fresh sperm (P = 0.000025). Two males were used per genotype; four sperm groups (epididymal, frozen epididymal, testicular and frozen testicular) were examined per male; approximately 15 (15.88 ± 6.52) oocytes were scored per group per male.