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In man brown eyes are dominant over blue...

In man brown eyes are dominant over blue eyes. A blue eyes mother and brown eyed father have 50% blue eyes and 50% brown eyes childred. What type of cross it involved?

A

Back cross

B

Test cross

C

Out cross

D

Reciprocal cross

Text Solution

AI Generated Solution

The correct Answer is:
To determine the type of genetic cross involved in the scenario where a blue-eyed mother and a brown-eyed father have 50% blue-eyed and 50% brown-eyed children, we can follow these steps: ### Step-by-Step Solution: 1. **Identify the Traits**: - In humans, brown eyes (B) are dominant over blue eyes (b). - Therefore, the genotypes can be represented as follows: - Brown-eyed individuals can be either homozygous (BB) or heterozygous (Bb). - Blue-eyed individuals must be homozygous recessive (bb). 2. **Identify the Parents' Genotypes**: - The blue-eyed mother must have the genotype **bb**. - The brown-eyed father, since he has offspring with 50% blue-eyed children, must be heterozygous, so his genotype is **Bb**. 3. **Determine the Gametes**: - The mother (bb) can only produce gametes with the allele **b**. - The father (Bb) can produce gametes with either **B** or **b**. 4. **Perform the Cross**: - We can set up a Punnett square to visualize the cross between the mother (bb) and the father (Bb): ``` B | b ----------------- b | Bb | bb ----------------- b | Bb | bb ``` - From the Punnett square, we see that: - 50% of the offspring will have the genotype **Bb** (brown eyes). - 50% of the offspring will have the genotype **bb** (blue eyes). 5. **Identify the Type of Cross**: - The type of cross where a hybrid (Bb) is crossed with a homozygous recessive (bb) parent is known as a **test cross**. - This type of cross is used to determine the genotype of an individual exhibiting a dominant trait. ### Conclusion: The type of cross involved in this scenario is a **test cross**.
To determine the type of genetic cross involved in the scenario where a blue-eyed mother and a brown-eyed father have 50% blue-eyed and 50% brown-eyed children, we can follow these steps: ### Step-by-Step Solution: 1. **Identify the Traits**: - In humans, brown eyes (B) are dominant over blue eyes (b). - Therefore, the genotypes can be represented as follows: - Brown-eyed individuals can be either homozygous (BB) or heterozygous (Bb). ...
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