Genetics practice worksheet featuring a Punnett square for cat hair traits.

Let’s solve this step by step.

We’re told:
- The dominant allele F = grey fur
- The recessive allele f = black fur
- Female dog is heterozygous → that means her genotype is Ff
- Male dog is homozygous recessive → that means his genotype is ff

We need to fill in the Punnett Square and find the % of possible genotypes and phenotypes.

---

Step 1: Set up the Punnett Square

The female (Ff) can give either F or f
The male (ff) can only give f (since both alleles are f)

So we set up the square like this:

```
| f | f |
-------------------------
F | Ff | Ff |
-------------------------
f | ff | ff |
```

Wait — actually, looking at the worksheet layout, it shows:

Top row (male gametes): two boxes labeled “f” and “f”
Left column (female gametes): one box labeled “F”, one labeled “f”

So the four inner boxes should be filled as:

- Top-left: F + f = Ff
- Top-right: F + f = Ff
- Bottom-left: f + f = ff
- Bottom-right: f + f = ff

So the completed Punnett Square looks like:

```
| f | f |
-------------------------
F | Ff | Ff |
-------------------------
f | ff | ff |
```

---

Step 2: Count the genotypes

There are 4 total offspring possibilities:

- FF: 0 → because no combination gives FF
- Ff: 2 → top-left and top-right
- ff: 2 → bottom-left and bottom-right

So percentages:

- FF = 0/4 = 0%
- Ff = 2/4 = 50%
- ff = 2/4 = 50%

---

Step 3: Determine phenotypes

Remember:
- F is dominant → so if there’s even one F, the dog is grey
- Only ff is black

So:

- Grey dogs: those with Ff → 2 out of 4 → 50%
- Black dogs: those with ff → 2 out of 4 → 50%

---

Final Check:

Genotypes:
- FF: 0%
- Ff: 50%
- ff: 50%

Phenotypes:
- Grey: 50%
- Black: 50%

This makes sense — when you cross a heterozygous parent (Ff) with a homozygous recessive (ff), you always get 50% dominant phenotype and 50% recessive phenotype.

---

Final Answer:

% of possible Genotypes:
FF = 0%
Ff = 50%
ff = 50%

% of possible Phenotypes:
Black fur = 50%
Grey fur = 50%