homozygote

Imagine getting one copy of a gene from each parent. When both copies are the same, the organism is called a homozygote. In genetics, this means it has two identical versions, called alleles, of the same gene.

This can happen in plants, animals, and humans. For example, an organism might get the same version of a gene from both parents, such as two copies for the same eye-color pattern or the same inherited trait. Sometimes this leads to a clear visible trait, and sometimes it matters more in how the trait can be passed on. The idea helps explain inheritance and why some traits stay stable across generations.

The term "homozygote" belongs to genetics, the study of how traits are passed from one generation to the next. It refers to an individual organism that has two identical alleles, or versions, of a gene at a specific place on its chromosomes. In simple terms, the two genetic instructions for that trait match each other.

You can picture this through Gregor Mendel's classic pea plant examples. If "T" stands for the allele for tallness and "t" stands for the allele for shortness, then a plant with "TT" is a homozygote for tallness, and a plant with "tt" is a homozygote for shortness. In both cases, the pair of alleles is the same. That is what makes the organism a homozygote.

This idea matters because matching alleles often make inheritance easier to predict. In simple genetics examples, homozygous organisms are sometimes described as "true-breeding" because they tend to pass on the same allele for that trait. A homozygote may be homozygous dominant, such as "TT," or homozygous recessive, such as "tt." Both fit the definition because the two alleles are identical.

The concept is also important in health and biology more broadly. Some inherited conditions appear only when a person has two copies of a recessive disease-causing allele, making that person a homozygote for that allele. More generally, the word helps scientists describe genetic patterns clearly when studying heredity, variation, and the way traits move through families and populations.