In humans, red-green colour blindness is recessive and sex-linked, while albinism is recessive and autosomal. A marriage between two homozygous parents a normal visioned albino woman and a colour blind and normally pigmented man will produce children

Options

A. who are all phenotypically normal visioned and have normal pigmentation
B. half of whom are colour-blind and the other hal having normal vision and all of them having normal pigmentation
C. all of whom have normal vision, but half of whom are albino and the other half with normal pigmentation.
D. of four categories, normal visioned, pigmented, normal visioned, albino, colour blind, pigmented, colour blind, albino, all in equal proportions

Answer

To solve the problem of determining the potential offspring of a normal visioned albino woman and a color blind, normally pigmented man, we will follow these steps:

### Step 1: Understand the Genetic Traits
- **Red-green color blindness** is a recessive trait linked to the X chromosome (sex-linked).
- **Albinism** is a recessive trait that is autosomal (not linked to sex chromosomes).

### Step 2: Determine the Genotypes of the Parents
- The **albino woman** is homozygous recessive for albinism (let's denote the allele for normal pigmentation as "A" and the allele for albinism as "a"). Therefore, her genotype is **aa** (for albinism) and she has normal vision, meaning she must have at least one dominant allele for normal vision. Since she is normal visioned but albino, her genotype for vision is **XX** (where X carries the normal vision allele).
- The **color blind man** is also homozygous for the color blindness trait. His genotype for color blindness is **X^cY** (where X^c represents the X chromosome carrying the allele for color blindness). He is normally pigmented, so he has the dominant allele for pigmentation, which we can represent as **A**. Therefore, his genotype is **AX^cY**.

### Step 3: Set Up the Punnett Square
To find the possible genotypes of their children, we can set up a Punnett square. The mother contributes either **X (normal vision)** or **X (normal vision)**, and the father contributes either **X^c (color blind)** or **Y**.

- **Mother's alleles**: X (normal vision) and X (normal vision)
- **Father's alleles**: X^c (color blind) and Y

### Step 4: Analyze the Offspring
From the Punnett square, we can derive the following possible combinations for their children:

1. **Female offspring**:
- X (from mother) and X^c (from father) = **XX^c** (carrier for color blindness, normal vision)
- X (from mother) and Y (from father) = **XY** (normal vision, normal pigmentation)

2. **Male offspring**:
- X (from mother) and Y (from father) = **XY** (normal vision, normal pigmentation)
- X^c (from mother) and Y (from father) = **X^cY** (color blind, normal pigmentation)

### Step 5: Conclusion
The children produced from this marriage will be:
- Female: XX^c (carrier for color blindness, normal vision)
- Male: XY (normal vision, normal pigmentation)

### Final Answer
All children will have normal vision and will be phenotypically normal in pigmentation. Therefore, the correct answer is that the offspring will be overall phenotypically normal visioned and have normal pigmentation.

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