Question

In pea plants, the trait for tall stems is dominant over the trait for short stems. if two heterozygous tall plants are crossed, what percentage of the offspring would be expected to have the same phenotype as the parents?

Answer 1

When crossing two heterozygous tall pea plants, the expected percentage of offspring that would be tall like the parents is 75%, as determined by the Punnett square showing a genotypic ratio of 1 TT, 2 Tt, and 1 tt, with only the tt genotype resulting in a short plant.

Step-by-step explanation:

When two heterozygous tall pea plants (Tt) are crossed, the likelihood of their offspring also exhibiting a tall phenotype can be determined using a Punnett square. A heterozygous tall plant (Tt) crossed with another heterozygous tall plant (Tt) would result in the following genotypic ratio: 1 TT (homozygous dominant), 2 Tt (heterozygous), and 1 tt (homozygous recessive).

Both the TT and Tt genotypes will display the tall phenotype, while the tt genotype will result in a short-stem phenotype. According to the genotypic ratio, we can predict that out of four offspring plants, three (or 75%) would be tall. This is because the 1 TT and 2 Tt plants all express the dominant tall trait. Therefore, the expected percentage of offspring that would have the same tall phenotype as the parents is 75%.