A woman with albinic father marries an ablinic man .The proportion of her progency is

Options

A. All normal
B. All albinic
C. 2 normal : 1 albinic
D. 1 normal : 1 albinic.

Answer

To solve the problem of determining the proportion of progeny from a woman with an albinic father who marries an albinic man, we can follow these steps:

### Step 1: Understand Albinism
Albinism is an autosomal recessive disorder. This means that an individual must inherit two copies of the recessive allele (denoted as 'a') to express the trait. The normal allele is denoted as 'A'.

### Step 2: Determine the Genotype of the Woman
Since the woman has an albinic father, her father must have the genotype 'aa' (homozygous recessive). The mother of the woman must have at least one normal allele, so her genotype could be either 'AA' (homozygous normal) or 'Aa' (heterozygous). However, since the woman has an albinic father, she must have inherited one 'a' from him. Therefore, her genotype must be 'Aa' (heterozygous).

### Step 3: Determine the Genotype of the Albinic Man
The albinic man must also have the genotype 'aa' since he expresses the albinism trait.

### Step 4: Set Up the Punnett Square
Now we can set up a Punnett square to determine the potential genotypes of their progeny. The genotypes involved in the cross are:
- Woman (Aa)
- Man (aa)

The Punnett square will look like this:

| | a | a |
|------|----|----|
| **A**| Aa | Aa |
| **a**| aa | aa |

### Step 5: Analyze the Results
From the Punnett square, we can see the possible genotypes of the progeny:
- 2 offspring with genotype 'Aa' (normal phenotype)
- 2 offspring with genotype 'aa' (albinic phenotype)

### Step 6: Calculate the Proportion
The ratio of normal to albinic offspring is:
- Normal (Aa): 2
- Albinic (aa): 2

This gives us a ratio of 2 normal : 2 albinic, which simplifies to 1 normal : 1 albinic.

### Conclusion
The proportion of the progeny from this cross is 1 normal : 1 albinic.

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