In genetics, what does the term homozygous mean?

The term homozygous refers specifically to an individual having two identical alleles for a particular trait. This means that both alleles, which are variants of a gene, are the same, whether they are dominant or recessive. For instance, if an organism has two alleles for a specific trait, such as eye color, and both alleles are for brown eyes, that organism is homozygous for brown eyes.

This concept is crucial for understanding how traits are expressed and inherited, as homozygous individuals will produce uniform gametes regarding that trait; they will always pass on the same allele to their offspring. This can lead to a direct expression of dominant traits or the expression of recessive traits when the organism is homozygous recessive. Understanding homozygosity versus heterozygosity (having two different alleles for a trait) helps clarify how specific traits may manifest in a population, which is essential in genetics and heredity studies.