Which statement describes a coisogenic animal?

Which statement describes a coisogenic animal?

• A. An animal that has no mutations
• B. An animal that has a mutation that was intentionally inserted
• C. An animal that has a single mutation that differs from other animals of that strain
• D. An animal that has mutations similar to those of other animals of that strain

Answer: (C)

Coisogenic animals are genetically identical to each other except for a single defined mutation. The rest of the genome comes from the same inbred strain, so every individual is the same except for that one locus. This allows researchers to attribute any observed differences to that specific mutation rather than to background genetic variation. The statement that best describes this is: an animal that has a single mutation that differs from other animals of that strain, because it highlights the single-locus difference against a uniform genetic background. The other descriptions don’t fit the concept: a wild-type animal has no such defined mutation; a mutation that was intentionally inserted could refer to broader genetic engineering not necessarily ensuring an otherwise identical background; and having mutations similar to others means there’s no unique single difference to compare.

Coisogenic animals are genetically identical to each other except for a single defined mutation. The rest of the genome comes from the same inbred strain, so every individual is the same except for that one locus. This allows researchers to attribute any observed differences to that specific mutation rather than to background genetic variation. The statement that best describes this is: an animal that has a single mutation that differs from other animals of that strain, because it highlights the single-locus difference against a uniform genetic background. The other descriptions don’t fit the concept: a wild-type animal has no such defined mutation; a mutation that was intentionally inserted could refer to broader genetic engineering not necessarily ensuring an otherwise identical background; and having mutations similar to others means there’s no unique single difference to compare.