Generation of transgenic prairie vole. Mean number of embryos recovered per superovulated female derived from distinct breeder pairs. The numbers of females examined per breeder pair (BP) are as follows: 7 for BP1, 7 for pair BP2, 7 for pair BP3, 9 for pair BP4, and 6 for pair BP5. Posthoc analysis indicates that BP 5 is significantly more sensitive to the superovulation paradigm than the other parental lineages. This data demonstrates that genetic background influences superovulation efficiency in the prairie vole. Error bars are represented as + SEM. Asterisk represents a significant p-value.