In mice, the allele for black coat color (B) is dominant over the brown allele (b). Two heterozygous mice are mated, and produce the following offspring: 20 black
4 brown

What is the EXPECTED FREQUENCY of black and brown mice in the offspring from this cross?

a. 5 black: 1 brown
b. 3 black: 1 brown
c. 2 black: 1 brown
d. 1 black: 3 brown

a. 5 black: 1 brown

Explanation:

This question involves a gene coding for coat color in mice. The allele for black coat color (B) is dominant over the brown allele (b). This means a mouse that is heterozygous for the Gene will have a black coat color.

According to this question, two heterozygous mice are mated i.e. Bb × Bb to produce the following offspring: 20 black mice and 4 brown mice.

Based on this result, the EXPECTED FREQUENCY of black and brown mice in the offsprings can be calculated;

20 black ÷ 4 = 5

4 brown ÷ 4 = 1

The expected frequency of black to brown is 5:1.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

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