Is it possible for a trait to be inherited by an organism but not expressed in its phenotype ?
Justify and illustrate your answer with a suitable Mendelian Cross.
Is it possible for a trait to be inherited by an organism but not expressed in its phenotype ?
Justify and illustrate your answer with a suitable Mendelian Cross.
Show Hint
Solution and Explanation
Yes, it is possible. A recessive trait can be inherited but not expressed when the organism also carries the dominant allele.
Step 2: Justify with Mendel dominance:
In a heterozygote the dominant allele masks the recessive allele.
The recessive allele is still present in the genotype and is passed on to gametes. So the organism is a carrier.
Step 3: Illustrate with a monohybrid cross:
Cross a homozygous tall pea plant (\(TT\)) with a homozygous dwarf plant (\(tt\)). Gametes are \(T\) and \(t\).
F1 plants are all \(Tt\) and all tall. The dwarf allele is inherited but not expressed.
Selfing F1: \(Tt \times Tt\). Gametes are \(T\) and \(t\) from each parent.
F2 genotypes: \(TT : Tt : tt = 1 : 2 : 1\). F2 phenotypes: 3 tall : 1 dwarf. The dwarf trait appears again in \(tt\) plants.
Final Answer:
Yes. The dwarf allele in tall \(Tt\) plants is inherited but hidden, and it reappears in the F2 as 3 tall : 1 dwarf.
\[ \boxed{\text{Yes, a recessive trait can be hidden in heterozygotes}} \]
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