Question

In horses, black (B) is the dominant color; brown (b) is the recessive color. Consider the cross seen here, between two black horses (Bb). What is the probability that these two horses will have a foal that is brown?
Responses
A 0%
B 25%
C 40%
D 50%

Answer 1

To determine the probability of two black horses (Bb) having a brown foal, we need to examine the possible genetic combinations of their offspring.

When two Bb (heterozygous black) horses are crossed, we can represent their alleles as follows:

- Parent 1: Bb
- Parent 2: Bb

We can use a Punnett square to visualize the genetic combinations:

```
B b
--------------
B | BB | Bb |
|-------|-------|
b | Bb | bb |
```

From the Punnett square, we see the following genetic combinations:
- BB: 1 (Black)
- Bb: 2 (Black)
- bb: 1 (Brown)

Now, we can calculate the probabilities:
- Probability of BB = 1/4
- Probability of Bb = 2/4 = 1/2
- Probability of bb = 1/4

Since "bb" represents the brown color, the probability of having a brown foal is 1 out of 4, or 25%.

Thus, the probability that these two horses will have a foal that is brown is **B 25%**.