Question

Question 29 It is found that in cha-cha chickens, the allele for a double comb (A) is dominant to the allele for a single comb (a). A mother with the genotype Aa and a father with the genotype Aa produce an offspring. What is the percent chance that the offspring will have a single comb? Word Bank: 7505025100 Blank 1:

Answer 1

To determine the percent chance that the offspring will have a single comb, we can use a Punnett square to evaluate the possible genotypes of the offspring from two parents that are both heterozygous (Aa).

The possible gametes from each parent (Aa) can be:

- A (from the first parent)
- a (from the first parent)

- A (from the second parent)
- a (from the second parent)

Setting up a Punnett square, we get:

```
A a
----------------
A | AA | Aa |
----------------
a | Aa | aa |
----------------
```

From the Punnett square, we can see the possible genotypes for the offspring:

- AA (double comb)
- Aa (double comb)
- Aa (double comb)
- aa (single comb)

Now, summarizing the genotypes:

- 1 AA
- 2 Aa
- 1 aa

Out of the 4 possible genotypes, only 1 (aa) corresponds to having a single comb.

To find the percent chance of the offspring having a single comb, we can use the ratio of the number of aa offspring to the total number of offspring:

\[
\text{Chance of single comb (aa)} = \frac{\text{Number of aa}}{\text{Total number of offspring}} = \frac{1}{4} = 0.25
\]

To express this as a percentage, we multiply by 100:

\[
0.25 \times 100 = 25\%
\]

Therefore, the percent chance that the offspring will have a single comb is **25**.

**Blank 1: 25**