[Campbell Biology P.829] If both A and B genes are suppressed in a flower according to the A... | Practice Question

If both A and B genes are suppressed in a flower according to the ABC hypothesis, what would be the expected floral organ arrangement from the outermost to the innermost whorl?

  • A: Sepals, Petals, Stamens, Carpels
  • B: Carpels, Stamens, Stamens, Carpels
  • C: Carpels, Carpels, Carpels, Carpels
  • D: Petals, Stamens, Stamens, Petals

Explanation

According to the ABC hypothesis, A gene activity normally inhibits C gene activity. If the A gene is suppressed, C gene activity expands into the first and second whorls. With both A and B genes suppressed, C gene activity would be present and unopposed in all four whorls. Therefore, all whorls sepals, petals, stamens, and carpels would develop into carpels, as carpel formation is solely dependent on C gene activity.