Evolution and speciation · USMLE Step 1

Which outcome is LEAST likely if two populations remain in contact and continue exchanging migrants (gene flow)?

  1. Reproductive isolation leading to speciation
  2. Genetic homogenization across the populations
  3. Decrease in genetic differentiation over time
  4. Increasingly shared allele frequencies between them
Show answer and explanation

Correct answer: Reproductive isolation leading to speciation

Ongoing gene flow homogenizes allele frequencies and reduces divergence, making speciation via reproductive isolation highly unlikely while migration continues.

Difficulty: Medium Question 13 of 20

Practice all 20 Evolution and speciation questions

Keep practicing

More Evolution and speciation questions