Fig. 1.

Vocalization rates were elevated in pups born to heterozygous dams. (A) Offspring from both wild type (WT) and heterozygous (het) dams (blue and red, respectively) were isolated, reunited, and reisolated for 5 min per session. Although WT and heterozygous pups from WT dams did not differ significantly in call rate or temporal pattern, pups from heterozygous dams were more vocal than pups from WT dams. (B) All groups but WT pups born from heterozygous dams exhibited maternal potentiation. Note the overall increase in calls from the heterozygous dam group (P < 0.001), and a three-way statistical interaction among isolation period × dam genotype × pup genotype (P = 0.015). *P < 0.05, **P < 0.01, ***P < 0.001.