Fig. 2.

Ccnb2^−/− mice show compromised fecundity. (A) Cumulative number of pups per female derived from different mating schemes. Mating schemes and number of pairs were as follows: +/+♂×+/+♀, n=20; +/−♂×+/−♀, n=35; −/−♂×−/−♀, n=6; +/+♂×−/−♀, n=6. Student's t-tests were performed between +/−♂×+/−♀ and −/−♂×−/−♀ (red asterisks) or +/−♂×+/−♀ and +/+♂×−/−♀ (blue asterisks); each point is the mean±s.e.m. of the number of pups obtained; **P<0.01, ***P<0.001. Breeding was initiated when the mice reached 8 weeks of age. (B) Pup body weights from +/−♂×+/−♀ matings were recorded 21 days after birth. The weight of each mouse was normalized for the average weight of the litter and plotted according to their genotype as medians with interquartile range. Student's t-tests were performed for statistical significance; ***P<0.0002. (C) Representative histological sections of ovaries from Ccnb2^+/+ and Ccnb2^−/− mice. Follicle stages were scored and representative pictures of pre-antral, early antral (when multiple cavities have not coalesced in a single antrum), late antral (when a single, large antrum is present) follicles and corpora lutea are shown. (D) Follicle counts were performed on pairs of ovaries from three biological replicates for each group and are plotted as mean±s.d. ns, not significant.