What does autosome mean?
An autosome is any chromosome in a cell's nucleus that is not a sex chromosome. While sex chromosomes (the X and Y chromosomes in mammals) determine an organism's biological sex, autosomes carry the genes responsible for most other inherited traits, from eye colour to enzyme function. Humans have 23 pairs of chromosomes in each body cell: 22 pairs of autosomes, plus one pair of sex chromosomes. Because everyone inherits two copies of each autosome — one from each parent — genes on autosomes typically influence both sexes in the same way, and disorders linked to them can be inherited in so-called autosomal dominant or autosomal recessive patterns. The word derives from Greek roots meaning 'same body', reflecting the fact that autosomes occur identically in males and females. The term belongs to formal scientific register and appears constantly in genetics textbooks, medical reports, and research literature on heredity.
nounAny of the chromosomes in a cell that are not sex chromosomes; autosomes carry the genes governing most inherited characteristics.
- Any chromosome other than a sex chromosome (an allosome); in humans, one of the 22 pairs of chromosomes shared by both sexes.
"Humans have 23 pairs of chromosomes, 22 of which are autosomes."
"The mutation was located on chromosome 7, one of the autosomes, which is why it affects males and females equally."
"In karyotype diagrams, the autosomes are numbered roughly in order of size, from largest to smallest."
Standard regular plural; the plural form is far more common than the singular because autosomes occur in sets.
"Each human cell contains 44 autosomes arranged in 22 homologous pairs."
Of your 46 chromosomes, only two determine your biological sex — the other 44 are autosomes doing most of the genetic heavy lifting.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of autosome
The word autosome was formed in the early twentieth century from the Greek prefix auto-, meaning 'self' or 'same', combined with -some, taken from the Greek sōma, meaning 'body'. The suffix had already been adopted in scientific English through the earlier coinage chromosome ('coloured body'), named for its stainability under microscopy. The name reflects the observation that these chromosomes are the same in both sexes, unlike sex chromosomes. The term shares its root with other '-some' scientific words such as ribosome and lysosome, and with adjectives like somatic.
Related word forms
How autosome is actually used
Autosome is a technical term used chiefly in genetics, medicine, and biology education; it is rare in everyday conversation. It is almost always discussed alongside sex chromosomes, and the derived adjective 'autosomal' appears frequently in phrases such as 'autosomal dominant' when describing patterns of inheritance.
Easily confused with autosome
A chromosome is any thread-like structure carrying genes in a cell, whereas an autosome is specifically one of the chromosomes that is NOT a sex chromosome.
An autotroph is an organism that makes its own food (from Greek 'self-feeding'), while an autosome is a non-sex chromosome; the two share only the prefix auto-.