Question

In mice, black fur color (B) is dominant over brown fur color(b). In a cross between two heterozygous mice. What is the probability of a black male mouse?

A
1/4

B
1/2

C
3/8

D
3/4

Answer 1

The correct answer is C. 3/8 as the probability of obtaining a black male mouse from a cross of two heterozygous mice (Bb x Bb). This takes into account the 3/4 probability of black fur and the 1/2 probability of the mouse being male.

Step-by-step explanation:

The question involves determining the probability of a phenotypic trait in a genetic cross, specifically, the probability of a black male mouse in a cross between two heterozygous mice for fur color, where black fur (B) is dominant over brown fur (b). To solve this, we use a Punnett square to illustrate the genetic crosses and calculate the probabilities.

For two heterozygous mice (Bb x Bb), the Punnett square would be:

• BB (black fur)
• Bb (black fur)
• Bb (black fur)
• bb (brown fur)

Since black fur is dominant, three out of the four possible genotypes result in black fur. To find the probability of getting a black male mouse, we have to consider the sex of the mice. Since mice have equal chances to be male or female, the probability of a black mouse being male is 1/2. Therefore, the probability of a black male mouse is 3/4 (the probability of black fur) multiplied by 1/2 (the probability of being male), which gives us 3/8.

Thus, the correct answer is C. 3/8, which is the probability of obtaining a black male mouse from this cross.