An autosome is a non-sex chromosome. It is an ordinarily paired type of chromosome that's the same in both sexes of a species. For example, in humans, there are 22 pairs of autosomes. The X and Y chromosomes are not autosomal. Non-autosomal chromosomes are usually referred to as sex chromosomes, allosomes or heterosomes. Like other chromosomes, autosomes display STR and SNP mutations which can be observed and have been used in genetic testings for ancestry, ethnicity, race and genealogical purpo… (More on Autosome)