autossomo

Autossomo, in biology, is the term used for any chromosome that is not a sex chromosome. In humans, there are 22 pairs of autosomes (chromosomes 1 through 22) and one pair of sex chromosomes (X and Y). Autosomes carry most of the organism’s genetic information and are present in homologous pairs in diploid individuals. Note that the term autossomo is used in Portuguese for the English term autosome.

Autosomes are inherited from both parents. Each offspring receives one chromosome from each autosomal pair from the father and one from the mother. During meiosis, autosomes undergo pairing and recombination, producing genetic variation. The majority of genes that determine ordinary traits reside on autosomes, though many traits are influenced by multiple genes and environmental factors.

Inheritance patterns for autosomal genes can be dominant or recessive. Autosomal aneuploidies arise from nondisjunction events and can produce conditions such as trisomy 21 (Down syndrome) or trisomies of other autosomes, often with significant consequences. Most autosomal disorders and traits are studied through Mendelian genetics or polygenic models, reflecting a mix of single-gene effects and broader genetic networks.

Not all sexually dimorphic traits are linked to sex chromosomes; some are influenced by autosomal genes. Nevertheless, the designation autosome is reserved for non-sex chromosomes, whereas sex determination is usually governed by sex chromosomes and related systems, which can vary across species.