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%
To determine the percentage of offspring that show the recessive phenotype in a Tt × Tt cross, we can use a Punnett square for analysis.
Step-by-Step Solution:
Parental Genotypes: Both parents are Tt (heterozygous).
Possible Gametes: Each parent can produce two types of gametes—T or t.
Punnett Square:
|
T (from Parent 1) |
t (from Parent 1) |
|
|
T (from Parent 2) |
TT (dominant) |
Tt (dominant) |
|
t (from Parent 2) |
Tt (dominant) |
tt (recessive) |
Genotypic Ratio:
- TT = 1 (25%)
- Tt = 2 (50%)
- tt = 1 (25%)
Phenotypic Ratio:
- Dominant phenotype (T-) = TT + Tt = 75%
- Recessive phenotype (tt) = 25%