When Tt x Tt are crossed, how many percent of the offsprings show a recessive phenotype?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 25%
T (tall) is dominant over t (dwarf). Both parents are Tt, so each makes two kinds of gametes in equal numbers: T and t.
| Gametes | T | t |
|---|---|---|
| T | TT | Tt |
| t | Tt | tt |
Genotypes: 1 TT : 2 Tt : 1 tt. TT and Tt both show the dominant trait; only tt shows the recessive trait.
Recessive offspring = 1 out of 4 = 25%. This is the familiar 3 : 1 phenotypic ratio of a monohybrid cross.