Autosomal chromosomes are the chromosomes 1-22 that determine the physical looks of the offspring
a sex chromosome is the 23rd chromosome that determines the sex of the offspring
An autosome basically is a non-sex chromosome and is a common paired, of chromosomes which is similar in both sexes of a kind. Like in human beings there are approximately twenty two pairs of autosomes and the X and Y chromosomes are not autosomal.
Where as a sex-determination system basically is a biological method which decides the expansion of sexual individuality in an organism, normally all sexual organisms have two sexes. In quiet a few cases, sex determination is mainly genetic, normally males as well as females have dissimilar alleles or even diverse genes that identify their sexual morphology.
An autosome prevailing gene is one on an autosome which is generally expressed, even while a distinct copy subsists. The probability is calculated at 1 in 2 for transmitting this autosomal dominant gene to a particular offspring.