HEREDITY
BACKCROSS OR TESTCROSS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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TT X Tt
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TT X TT
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Tt X Tt
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Tt X tt
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Detailed explanation-1: -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’
Detailed explanation-2: -Answer and Explanation: Since a Tt heterozygous, tall plant produce with equal probabilities the gametes T and t, and the tt homozygous, short plant only t gametes, when they are crossed (Tt x tt) the progeny will be 50% tall (all genotypically Tt) and 50% short (all genotypically tt).
Detailed explanation-3: -In F2 generation, the tall and dwarf plants will be produced in 3 : 1 ratio. Out of the three tall plants, one tall plant will be homozygous tall (TT) and two tall plants will be heterozygous tall (Tt).
Detailed explanation-4: -100 % Hint: Heterozygous is a condition when there are two different traits of a particular gene.
Detailed explanation-5: -In one of the experiments with pea plants, Mendel observed that when a homozygous tall pea plant (TT) is crossed with a homozygous dwarf pea plant (tt), in the first generation, only tall plants appear.