Allele: A variant form of a gene.
Gene: A unit of heredity that is responsible for a particular trait.
Example:
* A person with two copies of the allele for brown eyes is homozygous for brown eyes.
* A person with two copies of the allele for blue eyes is homozygous for blue eyes.
In contrast to homozygous, heterozygous refers to the condition of having two different alleles for a particular gene.
Significance of Homozygosity:
* Recessive traits: In recessive inheritance, individuals must be homozygous for the recessive allele to express the trait.
* Genetic disorders: Some genetic disorders are caused by recessive alleles, and individuals with two copies of the recessive allele will develop the disorder.
* Breeding: In agriculture, homozygous individuals are often preferred for breeding because they consistently produce offspring with the desired trait.
Note: Homozygosity can also refer to the state of having two identical copies of a chromosome, which is known as homozygosity by descent.
