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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homozygous (purebred)
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heterozygous (hybrid)
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Either A or B
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None of the above
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Detailed explanation-1: -If an organism has two copies of the same allele, for example AA or aa, it is homozygous for that trait.
Detailed explanation-2: -No, AA/bb is a pure-bred genotype, but Aa/Bb is a hybrid genotype. The possible genotypes of the pure-bred plants are AA/bb and aa/BB. Shull found that when he crossed the two pure-breds, the offspring grew much better. What is the genotype of the F1 hybrid offspring?
Detailed explanation-3: -Individuals with genotypes AA and aa are homozygotes (i.e., they have two copies of the same allele). Individuals with genotype Aa are heterozygotes (i.e., they have two different alleles at the A locus).
Detailed explanation-4: -A hybrid organism is one that is heterozygous, which means that is carries two different alleles at a particular genetic position, or locus. Therefore, a dihybrid organism is one that is heterozygous at two different genetic loci.