What does the term heterozygous describe?

The term heterozygous specifically describes an organism that possesses two different alleles for a particular gene. In genetics, alleles are different versions of the same gene that can exist at a specific locus on a chromosome. When an organism has two different alleles, one may be dominant and the other recessive, which can influence the organism's phenotype, or observable traits.

For instance, if the trait being evaluated is flower color, and one allele codes for purple flowers while the other codes for white, the organism is heterozygous. The dominant allele would typically mask the expression of the recessive one, resulting in purple flowers. Therefore, being heterozygous is crucial in understanding genetic variation and how different traits are expressed in organisms.