Some organisms have manifold copies of chromosome, diploid, triploid, tetraploid and so on. In traditional genetics, in a sexually reproduce organism (typically eukarya) the gamete has half the number of chromosomes of the somatic cell and the genome is a filled set of chromosomes in a gamete.
In haploid organisms, counting cells of bacteria, archaea, and in organelles counting mitochondria and chloroplasts, or viruses, that likewise hold genes, the single or set of circular and/or linear chains of DNA (or RNA for some viruses), likewise comprise the genome. The term genome can be practical specifically to mean that stored on a complete set of nuclear DNA (i.e., the "nuclear genome") but can also be applied to that stored within organelles that contain their own DNA, as with the "mitochondrial genome" or the "chloroplast genome". As well, the genome can comprise no chromosomal genetic elements such as viruses, plasmids, and transposable elements.
