Which gene is commonly implicated in parallel evolution of reduced armor plates in sticklebacks?

Which gene is commonly implicated in parallel evolution of reduced armor plates in sticklebacks?

• A. EDA
• B. Pitx1
• C. Gdf6
• D. Sox9

Answer: (A)

The main idea is that a single gene can drive repeated evolutionary changes across many populations. In sticklebacks, the number of lateral armor plates is largely controlled by the EDA gene. When regulatory changes reduce EDA expression, fish develop fewer plates, and this pattern has appeared independently in numerous freshwater populations, producing parallel evolution of reduced armor. The other genes listed are linked to different traits or broader aspects of skeletal development (for example, Pitx1 is famous for pelvic spine changes) and are not the primary drivers of armor-plate reduction seen across populations, so they don’t explain this repeated adaptation as clearly.

The main idea is that a single gene can drive repeated evolutionary changes across many populations. In sticklebacks, the number of lateral armor plates is largely controlled by the EDA gene. When regulatory changes reduce EDA expression, fish develop fewer plates, and this pattern has appeared independently in numerous freshwater populations, producing parallel evolution of reduced armor. The other genes listed are linked to different traits or broader aspects of skeletal development (for example, Pitx1 is famous for pelvic spine changes) and are not the primary drivers of armor-plate reduction seen across populations, so they don’t explain this repeated adaptation as clearly.