A and B genes are linked .what shall be genotype of progeny in a cross between AB/ab and ab/ab?

Options

A. AAbb and aabb
B. AaBb and aabb
C. AABB and aabb
D. aaBB `xx` Aabb

Answer

To solve the problem of determining the genotype of progeny in a cross between AB/ab and ab/ab, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Parent Genotypes**:
- The first parent has the genotype AB/ab, which means it is heterozygous for both genes A and B.
- The second parent has the genotype ab/ab, which means it is homozygous recessive for both genes.

2. **Understand Linked Genes**:
- Since genes A and B are linked, they are located close together on the same chromosome. This means they will be inherited together unless crossing over occurs, which is less likely due to their proximity.

3. **Determine Gamete Formation**:
- For the first parent (AB/ab), the possible gametes formed will be:
- AB (from the dominant alleles)
- ab (from the recessive alleles)
- The second parent (ab/ab) can only produce one type of gamete:
- ab (since both alleles are recessive).

4. **Perform the Cross**:
- Now, we can set up the cross between the gametes from both parents:
- From the first parent: AB and ab
- From the second parent: ab
- The possible combinations of gametes will be:
- AB (from the first parent) + ab (from the second parent) = AB/ab
- ab (from the first parent) + ab (from the second parent) = ab/ab

5. **List the Progeny Genotypes**:
- The progeny genotypes resulting from this cross will be:
- 50% AB/ab
- 50% ab/ab

### Final Answer:
The genotypes of the progeny in the cross between AB/ab and ab/ab will be:
- 50% AB/ab
- 50% ab/ab