GENETICS AND EVOLUTION
INHERITANCE AND VARIATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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two different alleles
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two identical alleles
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Different forms of the same gene
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only expressed if there are two copies
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Detailed explanation-1: -Individuals inherit two versions of each gene, known as alleles, from each parent. In the case of a recessive trait, the alleles of the trait-causing gene are the same, and both (recessive) alleles must be present to express the trait. A recessive allele does not produce a trait at all when only one copy is present.
Detailed explanation-2: -Recessive alleles only show their effect if the individual has two copies of the allele (also known as being homozygous?). For example, the allele for blue eyes is recessive, therefore to have blue eyes you need to have two copies of the ‘blue eye’ allele.
Detailed explanation-3: -When a trait is recessive, an individual must have two copies of a recessive allele to express the trait. Recessive alleles are denoted by a lowercase letter (a versus A).
Detailed explanation-4: -A recessive gene is only expressed when an organism has two recessive alleles for that gene. This is also known as being homozygous recessive. If an organism has one dominant and one recessive allele, it will show the dominant trait.
Detailed explanation-5: -A recessive trait is a trait that is expressed when an organism has two recessive alleles, or forms of a gene.