Term for Reappearance of Ancestral Trait

Reappearance of an ancestral trait, after several generations, is known as:

Correct Answer: Atavism

Atavism is the reappearance of an ancestral trait after it has been absent for several generations. It occurs when a dormant ancestral gene (or combination of genes) re-expresses itself in a descendant.

Key Points

• Atavism — ancestral trait reappears after many generations (e.g., extra toes in horses resembling three-toed ancestors).
• Mutation — sudden heritable change in genetic material (new change, not reappearance).
• Epistasis — one gene masks expression of another non-allelic gene.
• Linkage — two genes on the same chromosome inherited together.

Atavism differs from mutation because the ancestral gene was already present in the genome in a suppressed state, not newly created.