Definition

1. Adjective:
   • Having dissimilar alleles at a specific gene locus on homologous chromosomes: In genetics, "heterozygous" describes an individual organism that possesses two different forms (alleles) of a particular gene, one inherited from each parent, at a corresponding position (locus) on a pair of chromosomes.
   • Pertaining to a genetic condition of mixed alleles: It refers to the genetic state where the two alleles for a trait are not identical. This can result in the expression of a dominant trait if one allele is dominant, while the recessive allele is carried but not expressed in the organism's observable characteristics (phenotype).

Usage Examples

• Adjective:
  • The plant is heterozygous for flower color, carrying one allele for red flowers and one for white flowers.
  • Because the trait is recessive, only individuals who are not heterozygous or homozygous for it will show the condition.
  • Genetic testing revealed she was heterozygous for the gene variant, meaning she is a carrier but unaffected.

Advanced Usage

• Scientific Context: The term is primarily used in genetics, biology, and medicine.
  • The heterozygous advantage, such as in sickle cell trait, can provide increased resistance to certain diseases.
• "Heterozygous for": This is the standard construction to specify the trait or gene in question.
  • The mouse model was heterozygous for the knocked-out gene.

Variants and Related Words

• Heterozygosity (noun): The state or condition of being heterozygous; the proportion of heterozygous loci in an individual or population.
  • The population exhibited a high degree of genetic heterozygosity.
• Heterozygote (noun): An individual organism that is heterozygous for a particular gene or set of genes.
  • The heterozygote displayed the dominant phenotype.

Synonyms

• Mixed alleles (descriptive phrase)
• Dissimilar alleles (descriptive phrase)

Antonyms

• Homozygous (adjective): Having two identical alleles at a specific gene locus.
  • An organism homozygous for the dominant allele will express the dominant trait.

Adjective

1. having dissimilar alleles at corresponding chromosomal loci
   • heterozygous for eye color