GENETICS AND EVOLUTION
INHERITANCE AND VARIATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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test cross
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dominance
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dominant trait
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none of the above
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Detailed explanation-1: -Specifically, to detect the underlying genotype of an organism with a dominant phenotype, one must do a type of breeding analysis called a test cross. The test cross is another fundamental tool devised by Gregor Mendel.
Detailed explanation-2: -An organism with two dominant alleles for a trait is said to have a homozygous dominant genotype. Using the eye color example, this genotype is written BB.
Detailed explanation-3: -If the test cross results in any recessive offspring, then the parent organism is heterozygous for the allele in question. If the test cross results in only phenotypically dominant offspring, then the parent organism is homozygous dominant for the allele in question.
Detailed explanation-4: -A dominant allele is denoted by a capital letter (A versus a). Since each parent provides one allele, the possible combinations are: AA, Aa, and aa. Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.