[Campbell Biology P.595] Based on the provided experiment and its results, what is the prima... | Practice Question

Based on the provided experiment and its results, what is the primary conclusion regarding the cause of spine loss in lake stickleback fish?

  • A: The loss of spines is primarily due to a change in the coding sequence of the Pitx1 gene.
  • B: The loss of spines is primarily due to a change in the regulation of Pitx1 gene expression.
  • C: Both changes in coding sequence and gene expression regulation equally contribute to spine loss.
  • D: The exact cause of spine loss could not be determined from this experiment.

Explanation

The Conclusion section explicitly states: "The loss or reduction of ventral spines in lake populations of threespine stickleback fish appears to have resulted primarily from a change in the regulation of Pitx1 gene expression, not from a change in the gene's sequence."