In a particular species of flower, tall is dominant to short. Orange petals are dominant to the recessive white color. Using T/t
to symbolize the alleles for height, and F/f to symbolize the alleles for flower color. A homozygous tall, white flowering plant is crossed with a flower heterozygous for both traits. List the genotypes of the parents. What are the F1 genotypic and phentypic ratios
2 answers:
Answer: The parents phenotypes are TTff for a homozygous tall white flowering plant and TtFf for a plant heterozygous for both traits.
The genotypic ratio of the F1 offsprings is 4TTFf : 4TTff : 4TtFf : 4Ttff.
The phenotypic ratio of the F1 offsprings is 8 tall and orange flowering plants : 8 tall and white flowering plants.
Explanation: From the information provided, T is dominant to t while F is dominant to f. A plant that is homozygous for both tall and white flower will have two identical alleles for each trait, therefore its genotype will be TTff. A plant that is heterozygous for both traits will have one dominant allele and one recessive allele for each trait. Therefore its genotype will be TtFf.
A dibybrid cross between the two plants: TTff x TtFf will produce 16 offsprings with four possible genotypes: TTFf, TTff, TtFf and Ttff.
Out of the 16 offsprings, 4 are TTFf, 4 are TTff, 4 are TtFf and 4 are Ttff. Therefore, the genotypic ratio is 4TTFf : 4TTff : 4TtFf : 4Ttff.
TTFf and TtFf will manifest outwardly as tall and orange flowered while TTff and Ttff will manifest outwardly as tall and white flowered, therefore the phenotypic ratio is 8 tall and orange flowered plants : 8 tall and white flowered plants.
See the punnett square attached
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