NEET BIOLOGY

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GENETICS AND EVOLUTION

GENETIC BASIS OF INHERITANCE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A genetic cross of inbred snapdragons with red flowers with inbred snapdragons with white flowers resulted in F1 hybrid offspring that all had pink flowers. When the F1 plants were self-pollinated, the resulting F2 generation plants had a phenotypic ratio of 1 red:2 pink:1 white. The most likely explanation is:
A
pink flowers are the result of a blending of the red and white genotypes.
B
flower colour is due to 2 or more complementary genes.
C
heterozygous plants have a different phenotype than either inbred parent because of incomplete dominance of the dominant allele.
D
flower color inheritance in snapdragons does not behave as a Mendelian trait.
Explanation: 

Detailed explanation-1: -So, the correct option is ‘pink’

Detailed explanation-2: -A red snapdragon flower is crossed with a white snapdragon flower, and all the resulting flowers from the cross are pink.

Detailed explanation-3: -As mentioned earlier, incomplete dominance is a partial dominance, meaning the phenotype is in between the genotype dominant and recessive alleles. In the above example, the resulting offspring has a pink color trait despite the dominant red color and white color trait due to incomplete dominance.

Detailed explanation-4: -So, the correct answer is ‘Incomplete dominance’.

Detailed explanation-5: -Incomplete dominance The F1-hybrid plants have a different phenotype (pink flowers) than either of the true-breeding parents. This is an example of incomplete dominance.

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