Genetic cross between guinea pig parents with contrasting traits, showing allele combinations and potential offspring.

Let’s solve this step by step.

We are given two parent guinea pigs:

- Male Parent (left): Black, long hair → Genotype = Bbll
- Female Parent (right): White, short hair → Genotype = bbLL

We need to find the possible gametes each parent can make, then fill in the Punnett square with offspring genotypes and phenotypes.

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Step 1: Understand what alleles mean

In genetics:
- Capital letters = dominant trait
- Lowercase letters = recessive trait

For fur color:
- B = black (dominant)
- b = white (recessive)

For hair length:
- L = short hair (dominant) — wait! Let’s check the parents.

Wait — look at the male: he has long hair and genotype ll → so l = long hair, meaning L = short hair (since female is bbLL and has short hair).

So:
- Hair length: L = short (dominant), l = long (recessive)
- Color: B = black (dominant), b = white (recessive)

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Step 2: Find gametes for each parent

Gametes carry one allele for each gene.

#### Male Parent: Bbll

He has:
- For color: B or b
- For hair: only l (since ll)

So his gametes must be:
→ Bl and bl

But since he makes 4 gametes shown, and it's a dihybrid cross setup, we list all combinations. Since he is homozygous for hair (ll), both alleles are l. So:

Possible gametes from male:
Each gamete gets one color allele and one hair allele.

Color options: B or b
Hair options: l or l → always l

So gametes:
1. B + l = Bl
2. B + l = Bl
3. b + l = bl
4. b + l = bl

Actually, in standard notation, we write them as pairs: Bl, Bl, bl, bl — but since they’re identical within type, we often just say he produces two types: Bl and bl, each 50%.

But for the diagram, there are 4 circles under “Gametes” for each parent — probably to match the 4x4 grid later.

Similarly for female.

#### Female Parent: bbLL

She has:
- Color: b or b → always b
- Hair: L or L → always L

So her gametes:
Each gamete gets one color and one hair allele.

Color: b
Hair: L

So all her gametes are: bL

Again, 4 circles → so we write bL four times.

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Step 3: Set up the Punnett Square

The square is 4 rows (male gametes) x 4 columns (female gametes)

Male gametes (rows): Let’s assume order is: Bl, Bl, bl, bl
Female gametes (columns): bL, bL, bL, bL

Now combine each row and column:

Take first row: Male gamete = Bl
Combine with each female gamete (bL):

Offspring genotype = B from dad + b from mom → Bb
and l from dad + L from mom → Ll

So genotype = BbLl

Same for all 4 in first row → all BbLl

Second row: also Bl → same → all BbLl

Third row: Male gamete = bl
Combine with bL → b + b = bb, l + L = Ll → genotype = bbLl

Fourth row: same as third → all bbLl

So the 4x4 grid will have:

Rows 1 & 2: all BbLl
Rows 3 & 4: all bbLl

That’s 8 offspring with BbLl and 8 with bbLl? Wait no — 4 rows × 4 columns = 16 total.

Actually:

- Rows 1 and 2: 2 rows × 4 columns = 8 offspring → all BbLl
- Rows 3 and 4: 2 rows × 4 columns = 8 offspring → all bbLl

But let’s double-check:

Male gametes: if he is Bbll, he produces:

Actually, in meiosis, for two genes, even if one is homozygous, you still get 4 gametes in a 4x4 square for teaching purposes.

Standard way:

Parent 1: Bbll → gametes: Bl, Bl, bl, bl (but really only two unique types)

Parent 2: bbLL → gametes: bL, bL, bL, bL (only one unique type)

So when crossing:

Every combination:

Bl + bL → BbLl
Bl + bL → BbLl
bl + bL → bbLl
bl + bL → bbLl

And since each appears twice in the 4 gametes, in the 4x4 grid:

First two rows (Bl, Bl) crossed with 4 bL → 8 BbLl
Last two rows (bl, bl) crossed with 4 bL → 8 bbLl

Total 16 offspring.

Now, what do these genotypes mean for phenotype?

Recall:

- B_ = black (Bb or BB) → here Bb is black
- bb = white
- L_ = short hair (LL or Ll) → here Ll is short hair (since L is dominant)
- ll = long hair

So:

- BbLl → black, short hair
- bbLl → white, short hair

Therefore, all offspring have short hair (because all have at least one L), and half are black, half are white.

Specifically:

8 out of 16 = black, short hair
8 out of 16 = white, short hair

Or 50% black short, 50% white short.

Now, looking back at the diagram — the student is supposed to fill in the gametes and then the offspring in the squares.

Under "Gametes" for male (Bbll): should be Bl, Bl, bl, bl (or perhaps written as B l, B l, b l, b l — but usually combined)

Similarly, female (bbLL): bL, bL, bL, bL

Then in the big grid, each cell is the combination.

Since the question doesn’t ask for percentages or ratios explicitly, but to complete the diagram, I think we need to state what goes in the blanks.

But the user didn’t specify what exactly to output — however, based on context, likely they want the final phenotypic ratio or the completed cross.

Looking at the original image description, it seems like a worksheet where you fill in gametes and offspring.

But since we’re to provide final answer, and no specific question was asked beyond solving the problem, I’ll assume we need to report the expected offspring phenotypes.

From above:

All offspring have short hair (because mother contributes L, father contributes l, so all are Ll → short hair).

Color: half get B from father → black; half get b from father → white.

Mother always gives b.

So:

Phenotypes:

- 50% Black, Short Hair
- 50% White, Short Hair

Genotypes:

- 50% BbLl
- 50% bbLl

Now, to confirm calculations:

Male gametes: Bbll → probability of B is 1/2, b is 1/2; l is 1. So gametes: 1/2 Bl, 1/2 bl

Female gametes: bbLL → all bL

Offspring:

When male gives Bl (prob 1/2) + female bL → BbLl → black short

When male gives bl (prob 1/2) + female bL → bbLl → white short

So yes, 50-50.

In the 4x4 grid, since male has two Bl and two bl (if we duplicate for the diagram), and female has four bL, then:

Number of BbLl = 2 (male Bl) × 4 (female bL) = 8

Number of bbLl = 2 (male bl) × 4 (female bL) = 8

Total 16.

Phenotypes: 8 black short, 8 white short.

So final answer should reflect that.

But perhaps the question expects the filled-in gametes and offspring.

Since the instruction is to solve the problem accurately, and the problem is implied to complete the genetic cross, I'll summarize the result.

Final Answer:
The offspring will be 50% black with short hair (genotype BbLl) and 50% white with short hair (genotype bbLl). All offspring have short hair because the dominant allele for short hair (L) is inherited from the mother.