Question

Based on the Punnett square modeling the cross of two Hh Chihuahuas, what percentage of Chihuahua puppies should the breeder expect to have long hair?
• 100%
• 25%
• 75%
• 50%

Answer 1

To determine the percentage of Chihuahua puppies expected to have long hair from a cross between two Hh Chihuahuas, we need to understand the genetics involved.

In this case, "H" represents the allele for long hair (which is dominant), and "h" represents the allele for short hair (which is recessive).

When we perform the Punnett square for the cross of two Hh parents, we have:

- Parent 1: Hh
- Parent 2: Hh

The possible allele combinations for their offspring are as follows:

- HH (homozygous dominant) - long hair
- Hh (heterozygous) - long hair
- hH (heterozygous) - long hair
- hh (homozygous recessive) - short hair

The Punnett square would look like this:

```
H h
----------------
H | HH | Hh |
----------------
h | Hh | hh |
----------------
```

From the Punnett square, we see the following ratios:

- 1 HH (long hair)
- 2 Hh (long hair)
- 1 hh (short hair)

So, out of 4 possible genotypes, 3 of them (HH + Hh + Hh) result in long hair.

Calculating the percentage of puppies with long hair:

- Long hair (HH and Hh): 3 out of 4 = 3/4 = 75%

Therefore, the breeder should expect **75%** of the Chihuahua puppies to have long hair.

**Answer: 75%**