Does Gene Duplication Create New Information?
A duplicated gene initially produces another copy of information that already exists. Critics therefore argue that duplication itself does not explain the origin of genuinely new biological information or function.
Why This Matters
Gene duplication is frequently invoked in explanations of evolutionary innovation. Whether duplication merely increases the amount of existing DNA or provides a pathway to genuinely new functions is therefore directly relevant to claims about the creative capacity of evolutionary mechanisms.
Response
Duplication by itself initially creates an additional copy. The evolutionary explanation, however, does not normally stop at the duplication event. Duplicate copies can subsequently accumulate different mutations, divide ancestral functions, change their regulation, increase gene dosage, or acquire altered functions.
Comparative and experimental research documents duplicated genes with related but distinct functions, and several models describe how duplicates can be preserved long enough to diverge. Thus the relevant mechanism is duplication followed by modification and selection, not duplication alone.
This does not mean that invoking duplication automatically explains every proposed innovation. Particular cases still require evidence connecting duplication, divergence, and the resulting biological function.
Question That Remains
For major innovations attributed to gene duplication, can the historical sequence from the ancestral gene through duplication and divergence to the relevant new function be reconstructed with sufficient evidence?