Question 22

A gene is described as homozygous when the same allele is inherited from both parents.

When an individual inherits the same allele from each parent, they are said to be homozygous for that gene. This means both alleles at a particular locus are identical.

A) Homozygous

This option is correct because homozygous specifically refers to having two identical alleles for a particular gene, which is exactly what the question describes. When both parents contribute the same allele, the offspring is homozygous for that trait.

B) Dominant

Dominant refers to an allele that can mask the effect of a recessive allele when both are present. This option does not describe the situation where the same allele is inherited from both parents, as it focuses on the relationship between different alleles rather than the similarity of the alleles inherited.

C) Heterozygous

Heterozygous describes an individual who has inherited two different alleles for a gene, one from each parent. This is the opposite of what is described in the question, making this choice incorrect in the context provided.

D) Recessive

Recessive refers to an allele that does not produce a noticeable effect in the presence of a dominant allele. While a recessive allele can be part of a homozygous pair, the term itself does not describe the relationship of inheriting the same allele from both parents.

Conclusion

Homozygous is the only term that accurately describes the inheritance of the same allele from both parents, while the other options either refer to different genetic concepts or contradict the definition provided in the question. Therefore, option A is the definitive correct choice.