Genomic imprinting in the mammalian brain is hypothesized to regulate aspects of social behavior. These studies reveal regions of the mouse brain containing cell subpopulations with dominant maternal allele expression of dopa decarboxylase (Ddc), a monoamine neurotransmitter synthesis enzyme. Furthermore, it is shown that the behavioral consequences of Ddc heterozygous mutations is impacted by the parent of origin of the mutant allele.
