A tall plant is crossed with a short plant and all offspring are tall. Explain genetically.
This happens because the tall trait is dominant over the short trait.
Key Terms
| Term | Meaning |
|---|---|
| Dominant Trait | Trait that expresses even in presence of another |
| Recessive Trait | Trait that shows only when both alleles are same |
| Alleles | Different forms of a gene |
Genetic Explanation
| Parent | Genotype |
|---|---|
| Tall Plant | TT (homozygous dominant) |
| Short Plant | tt (homozygous recessive) |
Cross
| Gametes | T | T |
|---|---|---|
| t | Tt | Tt |
| t | Tt | Tt |
Result
| Offspring Genotype | Phenotype |
|---|---|
| All Tt | All Tall |
Stepwise Understanding
Tall parent has dominant allele (T)
Short parent has recessive allele (t)
Offspring receive one allele from each parent
All offspring get Tt combination
Dominant trait (Tall) is expressed
Important Concept
Dominant allele masks the expression of recessive allele.
Real Insight
Even though offspring carry the gene for short height (t), it does not show because dominant trait overrides it.
So all offspring appear tall due to dominance of the tall allele.