Each species can be identified by its karyotype . The karyotype is the full set of chromosomes of a species arranged with respect to number, size and shape of the chromosomes. The distribution of heterochromatin may also be taken into account.
Genome mutations result in a multiple set of chromosomes in a cell.
Organisms, tissues or cells that contain a multiple of n are called polyploid . Allopolyploidy may lead to the formation of new species . If multiple sets of the species own chromosomes occur as a result of its tissue differentiation, this is called somatic polyploidy or endopolyploidy . An organism that contains tissues with different states of ploidy is referred to as a cytochimera . It could also be described as a genetic mosaic.