True breeding tall peas are crossed with true breeding dwarf peas. The resulting progeny are all tall. This outcome tells you that:
tall dwarf is dominant to tall dwarf
and that you should use the symbols T/t D/d for the logic.
| P |
phenotype: Tall genotype: DD | x |
phenotype: Dwarf genotype: dd |
| F1 are all: |
phenotype: Tall genotype: Dd |
F1 x F1
| F2 | → D | → d |
| → D |
phenotype: Tall genotype: DD |
phenotype: Tall genotype: Dd |
| → d |
phenotype: Tall genotype: Dd |
phenotype: Dwarf genotype: dd |
The two possible test-crosses:
| F2 |
phenotype: Tall genotype: DD | x |
phenotype: Dwarf genotype: dd |
|
phenotype: Tall genotype: Dd |
phenotype: Tall genotype: Dd | |
|
phenotype: Tall genotype: Dd |
phenotype: Tall genotype: Dd |
and/or
| F2 |
phenotype: Tall genotype: Dd | x |
phenotype: Dwarf genotype: dd |
|
phenotype: Tall genotype: Dd |
phenotype: Tall genotype: Dd | |
|
phenotype: Dwarf genotype: dd |
phenotype: Dwarf genotype: dd |
This page © Ross E. Koning 1994.
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