What does it mean for an organism to be heterozygous?

In genetics, being heterozygous means that an organism has two different alleles for a particular gene. Genes can exist in different forms called alleles, and in a heterozygous individual, one allele is inherited from each parent, resulting in a pair of dissimilar alleles for a specific trait. This genetic variation can affect traits such as color, height, and resistance to certain diseases.

For instance, in a gene controlling flower color, if one parent contributes an allele for red petals and the other contributes an allele for white petals, the plant is heterozygous for that gene, with the resulting genotype being expressed in a distinct phenotype that may even exhibit a blend of the two colors (in cases of incomplete dominance) or favor one color over the other (in cases of complete dominance). This concept is fundamental in the study of inheritance and traits in organisms.