Which inheritance pattern requires mutations in at least one copy of each gene?

Digenic inheritance is characterized by the involvement of mutations in two different genes, which together contribute to a particular phenotype or condition. This form of genetic inheritance is notable because it requires both genes to have specific variations for the trait or disorder to manifest, meaning that mutations in at least one copy of each gene involved are necessary.

In digenic inheritance, it's important to understand that merely having a mutation in one gene is insufficient for the expression of the phenotype; the interaction between the variants in both genes is crucial. This contrasts with other modes of inheritance, such as monogenic disorders, which are caused by mutations in a single gene, or polygenic traits, which involve contributions from multiple genes but do not require mutations in all for the trait to be expressed.

The other choices pertain to ethical concepts rather than genetic inheritance patterns. Ambivalent decision making, ethic of care, and principle-based ethics relate to frameworks for making choices and moral considerations in healthcare but do not address genetic inheritance mechanisms.