homozygous

American  

[hoh-muh-zahy-guhs, hom-uh-] / ˌhoʊ məˈzaɪ gəs, ˌhɒm ə- /

Also homozygotic

adjective

Biology.

1. having identical pairs of genes for any given pair of hereditary characteristics.

2. of or relating to a homozygote.

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homozygous British  

/ -ˈzɪɡ-, ˌhɒm-, ˌhəʊməʊˈzaɪɡəs /

adjective

1. genetics (of an organism) having identical alleles for any one gene Compare heterozygous

   these two fruit flies are homozygous for red eye colour

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homozygous Scientific  

/ hō′mō-zī′gəs /

1. Relating to a cell that has two identical alleles for a particular trait at corresponding positions on homologous chromosomes.

2. Compare heterozygous

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Other Word Forms

• homozygosity noun
• homozygously adverb

Etymology

Origin of homozygous

1900–05; homo- + Greek -zygos; zygo-, -ous

Example Sentences

This has enriched rare functional variation, including recessive disorders and homozygous loss-of-function mutations, or “human knockouts.”

From The Wall Street Journal • Mar. 12, 2026

In Romito 2, researchers found a homozygous mutation in the NPR2 gene, which plays a key role in bone development.

From Science Daily • Feb. 17, 2026

Only two individuals in the second generation reproduce, and by chance these individuals are homozygous dominant for brown coat color.

From Textbooks • Jan. 1, 2015

For the F2 generation of a monohybrid cross, the following three possible combinations of genotypes result: homozygous dominant, heterozygous, or homozygous recessive.

From Textbooks • Apr. 25, 2013

There, between graphs of “Disease Specific Infant Mortality” and a description of “the homozygous state of Garrodian inborn errors,” was the photograph of Henrietta with her hands on her hips.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot