Final answer:
When two heterozygous individuals are crossed, the dominant trait will be expressed in the phenotype.
Step-by-step explanation:
When two heterozygous mice are crossed, each mouse carries one dominant and one recessive allele for a particular trait. Under typical conditions without involving imprinting, an offspring's phenotype would express the dominant trait if at least one dominant allele is present. However, the scenario provided mentions an imprint on the dominant allele of the female. Genetic imprinting is a phenomenon where genes are expressed in a parent-of-origin-specific manner. If the dominant allele of the female is imprinted (silenced), it will not be expressed even though it is present.
In the context of this specific question, if the imprinted allele is indeed the one that would determine the dominant phenotype and since it's silenced, the phenotype of the offspring will depend on the allele inherited from the male parent. If the male's contributed allele is dominant, the offspring's phenotype will be dominant; if it is recessive, the offspring's phenotype will be recessive.
Without information about the specific allele interactions, if imprinting results in the dominance not being expressed, then we cannot definitively determine the phenotype as dominant or recessive. However, if general Mendelian inheritance applies and the dominant allele being imprinted does not prevent its normal expression, the mother would typically express the dominant phenotype due to having at least one copy of the dominant allele.