Question

White feathers in canaries are dominant to yellow feathers. A heterozygous canary is crossed with a homozygous recessive canary. What ratio of the offspring will be homozygous recessive? 1 : 4 What percent of the offspring will be heterozygous? 25 %

Answer 1

2:4 homozygous recessive; 50% heterozygous.

Explanation:

I will be using the letter B to represent dominant alleles and b to represent recessive alleles.

If a canary is heterozygous, that means that it will have (Bb). Hetero, means different, so it will never be both (BB) or (bb).

If the other canary is homozygous recessive, it will be (bb). Homo, means the same, so it will never be (Bb). If the canary were homozygous dominant, it would be (BB).

I made a Punnett square to figure out the ratio and the percentage that is being asked in the question. As you can see, if you bring down the alleles from both of the parents accordingly, you will get...

2:4 of the offspring will be potentially homozygous recessive.

50% of the offspring will be heterozygous.