A true- breeding mutant strain of Drosophila has much smaller eyes than wild typ

Question

A true- breeding mutant strain of Drosophila has much smaller eyes than wild type. When males of this strain are mated to true-breeding wild type Drosophila females, all of the F1 offspring have eyes that are intermediate in size to the true-breeding parents. When the F1 males and females are mated, they produce offspring in the following ratio: 1 wild type eye: 2 intermediate-size eye: 1 small eye.

Using the format for naming mutant and wild type alleles of Drosophila genes, assign allele designations and write out the genotypes and phenotypes for the P-gen cross of the small-eyed males and wild type eye females, their F1 offspring, and the F2 offspring.

Explanation / Answer

The genotype of true- breeding mutant strain of Drosophila - ee.

The genotype of true- breeding wild strain of Drosophila - EE.

Parent generation EE(wild strain) x ee(mutant strain)

Gametes formed E e

F1 generation Ee(intermediate) x Ee --------------- self crossed

Gametes formed E and e E and e.

F2 generation

Genotypes of parent generation - EE and ee.

Wild type eye females with larger eye - EE.

Mutant strain of Drosophila with smaller eyes - ee.

F1 offspring generation - Ee, that all are intermediate-size eye.

F2 offspring generation - 1 Wild type eye females with larger eye, 2 intermediate-size eye and 1 Mutant type with smaller eyes.

Then the ratio of genotype and phenotype in F2 genaeration is 1:2:1, due to incomplete dominance.

Male/Female E e E EE(wild strain with larger eye) Ee(intermediate sized eye) e Ee(intermediate sized eye) ee(mutant strain with smaller eye)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.