What Is a Heterozygous Genotype?

According to Kansas State University, heterozygous genotypes are those that feature non-identical alleles for a given pair of genes. The term is most often used to describe an organism that has one copy of a recessive gene and one copy of a dominant gene. Because recessive traits are only expressed in an organism’s phenotype if they occur in pairs, such organisms appear normal, even though they possess the recessive gene.

According to the University of Washington, parent organisms that are heterozygous for a recessive gene can produce offspring in one of three combinations. The offspring can have both dominant alleles, both recessive alleles or one of each type of allele. Those offspring with two copies of either gene are homozygous, while the offspring that have both types of allele are called heterozygous.

Southwest Tennessee Community College lists a number of common recessive traits for humans, including short eyelashes, round eye shape and cleft chins. In order for a human to display any of these traits, he or she must have two copies of these genes. People who have only one copy of the gene, or heterozygous individuals, can pass the trait on to their offspring, but they do not display the trait themselves.