Question

this passage describes the wing type trait in fruit flies: some scientists breed fruit flies to learn how traits are inherited. these scientists often use flies with vestigial wings, which are shorter and stubbier than normal wings. fruit flies with vestigial wings cannot fly, so they are easier for scientists to handle and study. in a group of fruit flies, some individuals have normal wings and others have vestigial wings. in this group, the gene for the wing type trait has two alleles. the allele for vestigial wings (n) is recessive to the allele for normal wings (n). the punnett square below shows a cross between two fruit flies. consider the phenotypes and genotypes of the offspring shown. select all the boxes that represent offspring with a homozygous genotype that have vestigial wings. | | n | n | |---|---|---| | n | nn | nn | | n | nn | nn |

Explanation:

Step1: Recall genotype definitions

Homozygous genotype has two identical alleles (e.g., \(NN\) or \(nn\)). Recessive trait (vestigial wings) is expressed only in homozygous recessive (\(nn\)) since \(n\) is recessive to \(N\).

Step2: Analyze Punnett square cells

• \(NN\): Homozygous dominant, normal wings.
• \(Nn\): Heterozygous, normal wings (dominant allele present).
• \(nn\): Homozygous recessive, vestigial wings (matches the requirement: homozygous + vestigial wings).

Answer:

The box with genotype \(nn\) (the bottom - right box in the Punnett square)