[Campbell Biology P.570] Based on Figure 24.19 and the accompanying text, which of the follo... | Practice Question

Based on Figure 24.19 and the accompanying text, which of the following statements best explains the increase in fertility observed in the experimental hybrids from the F1 generation to the fifth hybrid generation?

  • A: The F1 hybrids successfully underwent allopolyploidization, doubling their chromosome number.
  • B: Natural selection eliminated regions of DNA from the parental species that were incompatible with one another.
  • C: Continuous backcrossing with parent species gradually introduced more compatible genes.
  • D: Mutations spontaneously arose in the hybrid genome, leading to the development of new, advantageous fertility genes.

Explanation

The conclusion section of Figure 24.19 clearly states that the rise in fertility was due to natural selection eliminating incompatible DNA regions from the parent species, making the hybrids more compatible and thus more fertile. The diagrams show mixed chromosomal segments in the later generations, supporting recombination and loss of incompatible segments.