In basic genetics terminology, what do you call a genotype that contains two identical alleles at a given gene locus (e.g., AA or aa)?

• A. Homozygous
• B. Hemizygous
• C. Heterozygous
• D. Polygenic

Answer: (A)

Verified step by step guidance

1. Understand that a genotype refers to the genetic makeup of an organism at a specific gene locus, which consists of two alleles—one inherited from each parent.
2. Recognize that when both alleles at a gene locus are identical (e.g., AA or aa), this condition has a specific term in genetics.
3. Recall the definitions of the terms: Homozygous means having two identical alleles; Heterozygous means having two different alleles; Hemizygous refers to having only one allele of a gene (common in sex chromosomes); Polygenic refers to traits controlled by multiple genes.
4. Match the condition of having two identical alleles to the correct term, which is 'Homozygous'.
5. Conclude that the genotype with two identical alleles at a gene locus is called homozygous.