Dominant and recessive traits Original Scenario-Based Download PDF

Questions

1. 1.

   On the crystalline peaks of Mount Zephyr, a field naturalist crosses two true-breeding strains of luminescent frost-beetles: one exhibiting metallic sapphire shells and the other displaying chalky white shells. All resulting first-generation (F1) beetles possess metallic sapphire shells, completely lacking any chalky appearance. When these F1 beetles are mated with one another, their second-generation (F2) offspring display a phenotypic ratio of roughly three sapphire beetles to one chalky white beetle. Which statement correctly explains the inheritance pattern of shell coloration in these beetles?

   • A) Chalky white shell coloration is a dominant trait because it requires two breeding cycles before its physical traits can be observed.
   • B) Metallic sapphire shell coloration is a recessive trait because it completely disappears whenever heterozygous pairings occur.
   • C) The hereditary factor for chalky white shells was destroyed in the F1 generation and regenerated anew through spontaneous mutations in F2 individuals.
   • D) Metallic sapphire shell coloration is a dominant trait, whereas chalky white shell coloration is a recessive trait masked in heterozygous individuals.