Question

Difficulty: MediumIncomplete Dominance, Codominance, and Multiple Alleles

In human ABO blood group inheritance, although three main alleles (IAI^A, IBI^B, and ii) exist within the human population, any normal diploid individual can possess at most two of these alleles.

Answer: Answer

Answer

The statement is true.
The statement is true because multiple allelism is a population-level concept describing three or more allele variants in a gene pool, whereas every diploid individual is constrained to carrying exactly two alleles for any autosomal gene locus.

Step-by-Step Solution

1
Define multiple allelism in population genetics.
The ABO blood group system exhibits multiple alleles (IAI^A, IBI^B, and ii) across the population.
Multiple alleles refer to three or more alternative forms of a gene occupying the same locus on homologous chromosomes across a species.
2
Analyze individual chromosomal makeup (ploidy).
Humans are diploid organisms with homologous chromosome pairs.
An individual inherits one set of 23 chromosomes from the egg cell and one set from the sperm cell.
3
Determine the maximum number of alleles per individual.
An individual can carry a maximum of two alleles at the ABO gene locus (e.g., IAIAI^A I^A, IAIBI^A I^B, IAiI^A i, IBIBI^B I^B, IBiI^B i, or iiii).
Since a gene locus exists only twice in a diploid cell (once per homologous chromosome), an individual can never possess three alleles.

Key Concept

Multiple Alleles vs Diploid Genotype
Estimated Time:1m 0s
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