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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a tall plant of different species
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a tall plant of the same species
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a dwarf plant of different species
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a dwarf plant of the same species
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Detailed explanation-1: -(C) (i)Genotype of dwarf plants will be ‘tt’ because dwarf-ness is a recessive trait that is expressed only when both the genes are recessive. (ii)Genotype of tall plant will be ‘TT’ because the parental cross is producing tall offspring always.
Detailed explanation-2: -As given in the question, the ratio between tall and dwarf plants in the offspring is 1 : 1, hence, the genotype of the tall plant is Tt. Q.
Detailed explanation-3: -The phenotypic ratio of 3:1 is observed when heterozygous plants are self-pollinated. Hence, genotype of parents is Tt and Tt.
Detailed explanation-4: -In a cross between heterozygous tall plants (Tt) and a homozygous dwarf plant (tt), the ratio in the offspring shall be 1 tall : 1 dwarf. This is because the heterozygous plant will make two types of gametes, one type having T allele and the other having t allele. Hence, the correct answer is ‘1 tall : 1 dwarf’