An individual with two different alleles is referred to as?

• A. Homozygous
• B. Heterozygous
• C. Aneuploid
• D. Polyploid

Answer: (B)

An individual with two different alleles is referred to as heterozygous. This term specifically describes the genotype of an organism when it possesses two different versions (alleles) of a particular gene, one inherited from each parent. For example, if an individual has one allele for brown eyes and another for blue eyes at a certain genetic locus, they are considered heterozygous at that locus.

In contrast, homozygous describes an individual with two identical alleles for a particular gene. Aneuploid refers to a condition where an individual has an abnormal number of chromosomes, which is unrelated to individual alleles at a specific gene locus. Polyploid indicates an organism having more than two complete sets of chromosomes, which is a different concept altogether. Thus, heterozygous is the correct term for an individual with two different alleles.