In plants known as four oclocks, the allele for red-flowers is incompletely dominant over the allele for white-flowers. What percent of the offspring would you expect to be pink in a cross between one white flower and one pink flower?

CODOMINANCE

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

In plants known as “four o’clocks”, the allele for red-flowers is incompletely dominant over the allele for white-flowers. What percent of the offspring would you expect to be pink in a cross between one white flower and one pink flower?

A	0%
B	25%
C	50%
D	100%

Explanation:

Detailed explanation-1: -24.In 4 o’clock plant, the gene for red flower colour (R) isincompletely dominant over the gene for white flowercolour (r), hence the plants heterozygous for flowercolour have pink flowers (Rr).

Detailed explanation-2: -Incomplete dominance was first observed in 4 ‘o’ clock plant. The allele responsible for red colour does not completely dominate the allele for white. The new phenotype pink arises by a “blend” of the dominant and recessive phenotypes.

Detailed explanation-3: -He took two true-breeding flower traits (red color as dominant allele and white color as a recessive allele) of four o’clock flowers and crossed them. The results show an intermediate heterozygote with pink color flowers (none of the alleles get dominant). This situation in inheritance is known as incomplete dominance.

Detailed explanation-4: -A red-flowered four-o’clock (any red-flowered four-o’clock) has the genotype RR; a white-flowered four-o’clock has the genotype rr. So, this cross is RR × rr. The F1 offspring will therefore all be Rr, all pink.

There is 1 question to complete.

AP BIOLOGY

HEREDITY

CODOMINANCE