Question

1. fruit flies are organisms commonly used in genetic studies. they reproduce quickly and have several traits that can be measured. one trait is the vestigial wing trait, which is recessive. most flies have red eyes, but the sepia eye trait is recessive. the image shows a mutant double recessive fly (ggee). a fly that is heterozygous for both traits (ggee) is crossed with one that has vestigial wings and sepia eyes (ggee). set up a punnett square and list the phenotypic ratio of the offspring. how many are normal wings, red eyes? __ how many are normal wings, sepia eyes? how many are vestigial wings, red eyes? how many are vestigial wings, sepia eyes? __

Explanation:

Step1: Determine Gametes

The heterozygous fly (GgEe) produces gametes: GE, Ge, gE, ge. The homozygous recessive fly (ggee) produces only ge gametes.

Step2: Set Up Punnett Square

	GE	Ge	gE	ge
ge	GgEe	Ggee	ggEe	ggee
ge	GgEe	Ggee	ggEe	ggee
ge	GgEe	Ggee	ggEe	ggee

Step3: Determine Phenotypes

• GgEe: Normal wings, red eyes
• Ggee: Normal wings, sepia eyes
• ggEe: Vestigial wings, red eyes
• ggee: Vestigial wings, sepia eyes

Step4: Count Phenotypes

• Normal wings, red eyes (GgEe): 4
• Normal wings, sepia eyes (Ggee): 4
• Vestigial wings, red eyes (ggEe): 4
• Vestigial wings, sepia eyes (ggee): 4

Answer:

Normal wings, red eyes: 4
Normal wings, sepia eyes: 4
Vestigial wings, red eyes: 4
Vestigial wings, sepia eyes: 4