A heterozygous individual carries how many different alleles for a given gene?

A heterozygous individual carries two different alleles for a given gene. This condition arises when an individual inherits one allele from one parent and a different allele from the other parent. For example, if the gene in question has two possible alleles, such as A and a, a heterozygous individual would have the genotype Aa. This genetic combination results in the presence of two variations of the gene, allowing for the expression of traits influenced by both alleles. In contrast, a homozygous individual possesses two identical alleles for a gene, but the defining characteristic of heterozygosity is the presence of two distinct alleles.