A Geneticist Is Studying a Particular Drosophila Mutant That Produces

Multiple Choice

A geneticist is studying a particular Drosophila mutant that produces a phenotype of "no wing" due to a mutation in a gene called wingless.She takes the mutant wingless and mutagenizes it.She hypothesizes that any fly that emerges with wings will be due to the original mutated gene reverting back to the wild- type allele. From this study,she identifies a fly that now has wings.When she sequences the wingless gene,she discovers that the original mutation is still there,and there are no other mutations in the wingless gene.However,a second gene at a separate locus is mutated.The second mutation is best classified as an__________.

A) null mutation
B) intragenic suppressor mutation
C) conditional mutation
D) intergenic suppressor mutation
E) haploinsufficiency mutation