A<unk>  is the characteristic chromosome complement of an eukaryote species. The preparation and study of<unk> s is part of cytogenetics.
In normal diploid organisms, autosomal chromosomes are present in two identical copies. There may, or may not, be sex chromosomes. Polyploid cells have multiple copies of chromosomes and haploid cells have single copies. The study of whole sets of chromosomes is sometimes known as karyology. The chromosomes are depicted (by rearranging a microphotograph) in a standard format known as a karyogram or idiogram: in pairs, ordered by size and position of centromere for chromosomes of the same size.
The study of<unk> s is made possible by staining: usually a suitable dye is applied after cells have been arrested during cell division by a solution of colchicine. Sometimes observations may be made on non-dividing (interphase) cells. The sex of an unborn fetus can be determined by observation of interphase cells (see amniotic centesis and Barr body).
Most (but not all) species have a standard<unk> . The normal human<unk> s contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes. Normal<unk> s for women contain two X chromosomes and are denoted 46,XX; men have both an X and a Y chromosome denoted 46,XY. However, some individuals have other<unk> s with added or missing chromosomes, and in all such cases there are developmental abnormalities as a consequence.<unk> s can be used for many purposes. They may be used to study chromosomal aberrations, to study cellular function, to study taxonomic relationships, or to gather information about past evolutionary events.
Karyotype
Cytogenetics
Genogram
Fetal screening
Obstetric ultrasonography
HCG pregnancy strip test
Amniocentesis
Triple test