Flower color is controlled by a single pair of alleles. The allele for red flowers is dominant to the allele for white flowers. A plant homozygous for red flowers is crossed with a plant homozygous for white flowers. All the resulting plants have red flowers (F1 generation). When the F1 generation crosses with each other, 18 plants are obtained. 12 plants have red flowers and 6 have white flowers (F2 generation). What ratio is expected in the F2 generation and what ratio has been obtained?
Correct answer: C. Option C
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation
The obtained ratio is 12 red to 6 white, hence 2:1. The expected ratio can be calculated by crossing two F1 generations: Bb x Bb will give BB; Bb; Bb; bb Hence the ratio is 3:1.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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