[Campbell Biology P.595] The "WHAT IF?" section asks what results would have led researchers... | Practice Question

The "WHAT IF?" section asks what results would have led researchers to conclude that a change in the coding sequence of the Pitx1 gene was more important than a change in regulation of gene expression for spine loss. Which of the following sets of hypothetical results would support this alternative conclusion?

  • A: Test of Hypothesis A: Result "Yes" (significant differences in Pitx1 coding sequence); Test of Hypothesis B: Result "No" (no differences in Pitx1 expression regulation).
  • B: Test of Hypothesis A: Result "No" (no differences in Pitx1 coding sequence); Test of Hypothesis B: Result "Yes" (significant differences in Pitx1 expression regulation).
  • C: Test of Hypothesis A: Result "Yes" (significant differences in Pitx1 coding sequence); Test of Hypothesis B: Result "Yes" (significant differences in Pitx1 expression regulation).
  • D: Test of Hypothesis A: Result "No" (no differences in Pitx1 coding sequence); Test of Hypothesis B: Result "No" (no differences in Pitx1 expression regulation).

Explanation

For a change in the coding sequence to be 'more important,' it would need to show significant differences supporting Hypothesis A while the regulation of gene expression would need to show no significant differences rejecting Hypothesis B . This scenario would directly contradict the actual experimental findings and lead to the alternative conclusion.