A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities.
Alternatively, the human genome can be classified as follows, based on pairing, sex differences, as well as location within the cell nucleus versus inside mitochondria:
22 homologous autosomal chromosome pairs (chromosomes 1 to 22). Homologous means that they have the same genes in the same loci, and autosomal means that they are not sex chromomes.
Two sex chromosome (in green rectangle at bottom right in the schematic karyogram, with adjacent silhouettes of typical representative phenotypes): The most common karyotypes for females contain two X chromosomes and are denoted 46,XX; males usually have both an X and a Y chromosome denoted 46,XY. However, approximately 0.018% percent [ <2 out of 10,000] of humans are intersex, sometimes due to variations in sex chromosomes.
