Question

Which of the following would be true of a plant heterozygous for a single gene controlling flower color? (Assume complete dominance).
a) It will produce gametes with recessive flower color alleles and gametes with dominant flower color alleles in about a 3:1 ratio.
b) It displays the recessive flower color.
c) If crossed with another heterozygous plant, the majority of progeny will have the dominant flower color.
d) About half of all its progeny will display the recessive flower color.

Answer 1

Answer:

C: If crossed with another heterozygous plant, the majority of progeny will have the dominant flower color.

Explanation:

Assuming the gene is represented an allele A, purple colour can be AA or Aa while white colour will be aa.

If a heterozygous plant Aa is crossed with another heterozygous Aa, the genotype of the progeny will be AA, Aa, Aa and aa.

Since allele A is dominant over a, it thus means that the phenotype of the progeny will be 3 purple and 1 white flowered plant.

Hence, the majority of the progeny will have the dominant (75%) flower colour.

The correct option is C.