Homozygous mice carrying a null mutation for the DARPP - 32 gene exhibited minimal levels of P - facilitated sexual receptivity when compared to their wild - type littermates. (science.sciencemag.org)
As the team reports online this week in Proceedings of the National Academy of Sciences, the homozygous mice didn't make the ultrasonic sounds that young mice emit when separated from their mothers. (sciencemag.org)
When maintaining a live colony at The Jackson Laboratory Repository, homozygous mice may be bred together. (jax.org)