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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RR and rr
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RR, Rr and rr
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RRrr
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only Rr
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Detailed explanation-1: -RR x rr. You’ll note that 100% of all offspring are Rr, which is the genotype. Since the genotype for all offspring are the same, and the Rr genotype encodes a pink color, then 100% of the phenotypes will be pink (NOT red-remember that this is incomplete dominance).
Detailed explanation-2: -The cross between Rr, a plant with heterozygous condition for red flowers and rr, a plant with homozygous recessive condition with white flowers will produce two types of genotypes in progeny-Rr and rr in equal proportions.
Detailed explanation-3: -The (RR) genotype is homozygous dominant and the (rr) genotype is homozygous recessive for seed shape. In the image above, a monohybrid cross is performed between plants that are heterozygous for round seed shape. The predicted inheritance pattern of the offspring results in a 1:2:1 ratio of the genotype.