Homozygous (/ˌhoʊməˈzaɪɡəs/) is a biology term used to describe an organism having identical alleles for a particular gene. The spelling of the word can be explained using the International Phonetic Alphabet (IPA) as follows: The first syllable "ho" is pronounced as /hoʊ/, the second syllable "mo" is pronounced as /mə/, while the third syllable "zyg" is pronounced as /zaɪɡ/. The final syllable "ous" is pronounced as /əs/. Hence, the correct way to spell and pronounce this word is /ˌhoʊməˈzaɪɡəs/.
Homozygous is an adjective used to describe an organism that has identical alleles for a particular gene. Alleles are alternative forms of a gene that occur on the same locus (position) on a pair of homologous chromosomes. Each individual inherits one allele for each gene from each parent, and if both alleles for a gene are the same, the organism is said to be homozygous for that gene.
In a homozygous individual, both alleles are either dominant or recessive, meaning they possess the same genetic information. For instance, if an organism inherits two dominant alleles (AA) for a gene, it is homozygous dominant, and if it inherits two recessive alleles (aa), it is homozygous recessive. On the other hand, if an individual has two different alleles (Aa), it is said to be heterozygous for that gene.
Homozygosity plays a crucial role in genetics, as it influences the expression and inheritance of traits. In homozygous dominant individuals, the dominant allele will always be expressed in the phenotype (observable traits), while homozygous recessive individuals will express the recessive allele. It is important to note that homozygous organisms can only pass on one version of a gene to their offspring, making them more predictable in terms of inheritance compared to heterozygotes.
Relating to homozygosis; produced by the union of similar gametes.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "homozygous" originates from the combination of two Greek roots: "homoios" meaning "the same" or "equal", and "zygon" meaning "yoke" or "pair". Therefore, "homozygous" can be literally translated as "having the same yoke" or "having an equal pair". This term is commonly used in genetics to describe an organism that has two identical copies of a particular gene.