PATHOLOGY MCQ
GENETICS AND DISEASE
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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multiple alleles.
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incomplete dominance.
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polygenic inheritance.
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sex-linked traits.
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Detailed explanation-1: -The A, B, AB and O blood group types in humans are determined by three alleles of a gene. The gene I, which determines the blood type, exists in three allelic forms, which are IA, IB and i.
Detailed explanation-2: -Multiple Allele Traits The majority of human genes are thought to have more than two normal versions or alleles. Traits controlled by a single gene with more than two alleles are called multiple allele traits. An example is ABO blood type.
Detailed explanation-3: -The ABO blood group antigens are encoded by one genetic locus, the ABO locus, which has three alternative (allelic) forms-A, B, and O. A child receives one of the three alleles from each parent, giving rise to six possible genotypes and four possible blood types (phenotypes).
Detailed explanation-4: -The four main blood groups A, B, AB, and O are controlled by three alleles: A, B, and O. As humans are diploid, only two of these can be present in any one genotype. In other words, only two of these alleles are present at the same time in a person’s cell.
Detailed explanation-5: -The human ABO blood group system exhibits codominance. The system consists of three alleles A, B, and O. Both A and B are dominant in relation to O, and therefore blood group A can have the genotype AA or AO.