Practicing Monohybrid Crosses in Canaries: Understanding Genetic Ratios
What is the ratio of the offspring that are homozygous to the total number of offspring?
When practicing monohybrid crosses with white feathers in canaries dominant to yellow feathers, a heterozygous canary is crossed with a homozygous recessive canary. What would be the ratio of the offspring that are homozygous to the total number of offspring?
Answer:
The ratio of homozygous recessive (ww) offspring to the total number of offspring from a cross of a heterozygous canary (Ww) and a homozygous recessive canary (ww) would be 1:2.
When considering the monohybrid cross where white feathers in canaries are dominant to yellow feathers, and a heterozygous canary (Ww) is crossed with a homozygous recessive canary (ww), we can set up a Punnett square to predict the outcome of the offspring. In this monohybrid cross, there are two possible genotypes for the offspring resulting from this pairing: Ww (heterozygous) and ww (homozygous recessive).
To predict the ratio of homozygous offspring to the total number of offspring, we need only consider the ww outcome. Since the Punnett square would show equal likelihood for Ww and ww, we can conclude that half of the offspring will be homozygous recessive (ww). Therefore, the ratio of homozygous recessive offspring to the total would be 1:2, or 1 homozygous recessive for every 2 total offspring.