A fictional lizard population has a gene called Fire1. The dominant allele of this gene allows the lizard to produce a combustion reaction from glands in the back of their throat. A second gene, Fire2, codes for a protein that suppresses the expression of the Fire1 gene.
The lizard population is not fire-breathing, but genetic analysis reveals that a majority of the lizards have at least one copy of the dominant Fire1 allele.
Which of the following would be expected if a mutagen that targets the Fire2 gene was released into the lizard's environment?