Question

A black Bb (codominant) bird mates with a red Rr (codominant) bird. Both b and r are recessive for brown. What will the offspring be? Complete the Punnett square.
a. What is the probability of having a black bird?

b. What is the probability of having a red bird?

c. What is the probability of having a black and red bird?

d. What is the probability of having a brown bird?

Answer 1

Answer:

a. The probability of having a black bird is 25%.

b. The probability of having a red bird is 25%.

c. The probability of having a black and red bird is 25%.

d. The probability of having a brown bird is 25%.

Explanation:

A black Bb (codominant) bird mates produces two types of gamete: B and b.

B is the dominant allele, and b is the recessive allele in the pair of alleles B and b.

A red Rr (codominant) bird gives two types of gamete: R and r.

R is the dominant allele, and r is the recessive allele in the pair of alleles R and r.

The Bb x Rr cross can be seen in the image attached here.

The offspring may have one of the four genotypes: BR, Br, bR and br.

As these two pairs of alleles (B, b, and R, r) are codominant, birds with BR genotype have black&red feathers, those with Br genotype have black feathers, those with bR genotype have red feathers, and those with br genotype have brown feathers.

According to the Punnette square, each of these four genotypes accounts for 25%.

Therefore, the probability of having a black bird, a red bird, a black&red bird, or a brown bird is 25%.