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noun, plural: autosomes

(Science: Genetics)

Any chromosome not considered as a sex chromosome, or is not involved in sex determination. It occurs in pairs in somatic cells and singly in sex cells (gametes).


For instance, a human somatic cell will normally contain 23 pairs of chromosomes (total=46 chromosomes). Twenty-two (22) of these pairs will be autosomes, and only one of them will be a pair of sex chromosomes (the X and Y chromosomes).

In sex cells like egg cell and sperm cell where chromosomes occur singly (total=23), 22 of them are autosomes while the remaining one is a sex chromosome (either X or Y chromosome).

Word origin: Gk, comb. form of autós ,self + Gk soma, body.

Related forms: autosomal (adjective).

Synonym: euchromosome.
Compare: sex chromosome.
See also: chromosomes.