Which scenario best describes multiple alleles?

Which scenario best describes multiple alleles?

• A. A gene with only dominant and recessive alleles
• B. A trait influenced by more than two alleles
• C. An allele that completely masks another
• D. A gene that shows only homozygous traits

Answer: (B)

The concept of multiple alleles refers to a situation where a gene has more than two variations or alleles present at a specific locus in the population. Option B accurately describes this scenario by indicating that a trait is influenced by more than two alleles. For example, the ABO blood group system in humans is determined by three alleles: I^A, I^B, and i. This leads to four possible blood types (A, B, AB, and O), demonstrating how the interplay of multiple alleles can influence a single phenotypic trait. The other options do not capture the essence of multiple alleles. A scenario with only dominant and recessive alleles does not encompass the concept of multiple alleles since it suggests just two variants. While an allele that completely masks another refers more to dominance relationships among alleles rather than the number of alleles itself, a gene that shows only homozygous traits implies limited genetic variation, which contradicts the premise of multiple alleles. Therefore, option B stands out as the only choice that truly reflects the definition of multiple alleles.

The concept of multiple alleles refers to a situation where a gene has more than two variations or alleles present at a specific locus in the population. Option B accurately describes this scenario by indicating that a trait is influenced by more than two alleles. For example, the ABO blood group system in humans is determined by three alleles: I^A, I^B, and i. This leads to four possible blood types (A, B, AB, and O), demonstrating how the interplay of multiple alleles can influence a single phenotypic trait.

The other options do not capture the essence of multiple alleles. A scenario with only dominant and recessive alleles does not encompass the concept of multiple alleles since it suggests just two variants. While an allele that completely masks another refers more to dominance relationships among alleles rather than the number of alleles itself, a gene that shows only homozygous traits implies limited genetic variation, which contradicts the premise of multiple alleles. Therefore, option B stands out as the only choice that truly reflects the definition of multiple alleles.