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Question
In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F1 generation pink flowers were obtained. When pink flowers were selfed, the F2 generation showed white, red and pink flowers.
Choose the incorrect statement from the following.
In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F1 generation pink flowers were obtained. When pink flowers were selfed, the F2 generation showed white, red and pink flowers.
Choose the incorrect statement from the following.
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Solution
The correct option is A Law of segregation does not apply in this experiment
Mendel’s law of dominance states that when parents with pure, contrasting traits are crossed, then only one form of trait appears in theF1 generation out of the two traits. The trait that appears in the F1 hybrid is called the dominant trait. Hence, in case of dominance, the F1 hybrid resembles either of the parents.
When Mendel’s experiments were repeated in different plants, it was found that sometimes theF1 had a phenotype that did not resemble either of the two parents and was intermediate between the two. The inheritance of flower colour in the dog flower (snapdragon or Antirrhinum sp.) is a good example of this.
In a cross between true-breeding red-flowered (RR) and true-breeding white-flowered plants (rr), the F1 (Rr) plant was pink-flowered.
When the F1 undergoes self-pollination, the F2 generation has offspring in the following ratio.
1 (RR) Red: 2 (Rr) Pink: 1 (rr) White. This phenomenon is known as incomplete dominance.
As this experiment does not follow the principle of dominance, option b is correct.
The intermediate phenotype of pink colour in the F1 is due to incomplete dominance and hence option c is correct.
In incomplete dominance, the phenotypic ratio of F2 is 1 4 (Red) : 24 (Pink) : 14 (White)and hence option d is correct.
Law of segregation states that, during gamete formation, the two alleles controlling a character segregate, such that each gamete receives only one allele out of the pair. The law of segregation is universal and holds good in all cases.
Hence, option a is incorrect.
Mendel’s law of dominance states that when parents with pure, contrasting traits are crossed, then only one form of trait appears in theF1 generation out of the two traits. The trait that appears in the F1 hybrid is called the dominant trait. Hence, in case of dominance, the F1 hybrid resembles either of the parents.
When Mendel’s experiments were repeated in different plants, it was found that sometimes theF1 had a phenotype that did not resemble either of the two parents and was intermediate between the two. The inheritance of flower colour in the dog flower (snapdragon or Antirrhinum sp.) is a good example of this.
In a cross between true-breeding red-flowered (RR) and true-breeding white-flowered plants (rr), the F1 (Rr) plant was pink-flowered.
When the F1 undergoes self-pollination, the F2 generation has offspring in the following ratio.
1 (RR) Red: 2 (Rr) Pink: 1 (rr) White. This phenomenon is known as incomplete dominance.
As this experiment does not follow the principle of dominance, option b is correct.
The intermediate phenotype of pink colour in the F1 is due to incomplete dominance and hence option c is correct.
In incomplete dominance, the phenotypic ratio of F2 is 1 4 (Red) : 24 (Pink) : 14 (White)and hence option d is correct.
Law of segregation states that, during gamete formation, the two alleles controlling a character segregate, such that each gamete receives only one allele out of the pair. The law of segregation is universal and holds good in all cases.
Hence, option a is incorrect.
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