GENETICS AND EVOLUTION
GENETIC BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Both parents passed the gene for white flowers to five of their offspring.
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One parent passed on two genes for white flowers to five of its offspring.
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The trait for white flowers is dominant, and both parents passed it to the offspring.
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A mutation occurred in one of the offspring, resulting in white flowers, and the mutation spread to four other offspring.
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Detailed explanation-1: -Mendel noted that hybridizing true-breeding (P generation) plants gave rise to an F1 generation that showed only one trait of a characteristic. For example, a true-breeding purple-flowering plant crossed with a true-breeding white-flowering plant always gave rise to purple-flowered hybrid plants.
Detailed explanation-2: -Answer and Explanation: Assuming that purple flowers are dominant to white flowers, the only way that two purple-flowered plants could produce plants with white flowers is if the purple plants were heterozygous.
Detailed explanation-3: -There was a 3:1 ratio of purple:white flowers in generation F2 because the “masked” (recessive) genes from the F1 generation were allowed to pair, however they were only allowed to pair one time leaving the other three times to appear with purple flowers.
Detailed explanation-4: -Answer and Explanation: Genotype of pure breed purple flowered plant will be PP. Genotype of pure breed white flowered plant will be pp. Therefore, ratio of dominant to recessive phenotype will be 1:0.