Editing DNA (section)

=== Amount ===
[[File:Human karyotype with bands and sub-bands.png|thumb|Schematic [[karyotype|karyogram]] of a human. It shows 22 [[homologous chromosome]]s, both the female (XX) and male (XY) versions of the [[sex chromosome]] (bottom right), as well as the [[human mitochondrial genetics|mitochondrial genome]] (to scale at bottom left). The blue scale to the left of each chromosome pair (and the mitochondrial genome) shows its length in terms of millions of DNA [[base pair]]s.{{further|Karyotype}}]]
In humans, the total female [[diploid]] [[nuclear genome]] per cell extends for 6.37 Gigabase pairs (Gbp), is 208.23&nbsp;cm long and weighs 6.51 picograms (pg).<ref name="pmid30813969">{{cite journal| vauthors=Piovesan A, Pelleri MC, Antonaros F, Strippoli P, Caracausi M, Vitale L| title=On the length, weight and GC content of the human genome. | journal=BMC Res Notes | year= 2019 | volume= 12 | issue= 1 | pages= 106 | pmid=30813969 | doi=10.1186/s13104-019-4137-z | pmc=6391780 | doi-access=free }}</ref> Male values are 6.27 Gbp, 205.00&nbsp;cm, 6.41 pg.<ref name="pmid30813969"/> Each DNA polymer can contain hundreds of millions of nucleotides, such as in [[chromosome 1]]. Chromosome 1 is the largest human [[chromosome]] with approximately 220 million [[base pair]]s, and would be {{val|85|u=mm}} long if straightened.<ref name="Gregory_2006" />

In [[eukaryote]]s, in addition to [[nuclear DNA]], there is also [[mitochondrial DNA]] (mtDNA) which encodes certain proteins used by the mitochondria. The mtDNA is usually relatively small in comparison to the nuclear DNA. For example, the [[Human mitochondrial genetics|human mitochondrial DNA]] forms closed circular molecules, each of which contains 16,569<ref name="Anderson_1981">{{cite journal | vauthors = Anderson S, Bankier AT, Barrell BG, de Bruijn MH, Coulson AR, Drouin J, Eperon IC, Nierlich DP, Roe BA, Sanger F, Schreier PH, Smith AJ, Staden R, Young IG | display-authors = 6 | title = Sequence and organization of the human mitochondrial genome | journal = Nature | volume = 290 | issue = 5806 | pages = 457–465 | date = April 1981 | pmid = 7219534 | doi = 10.1038/290457a0 | s2cid = 4355527 | bibcode = 1981Natur.290..457A }}</ref><ref>{{Cite web |url=http://chemistry.umeche.maine.edu/CHY431/MitoDNA.html |title=Untitled |access-date=2012-06-13 |archive-url=https://web.archive.org/web/20110813123936/http://chemistry.umeche.maine.edu/CHY431/MitoDNA.html |archive-date=2011-08-13 |url-status=dead }}</ref> DNA base pairs,<ref name=Satoh1991>{{cite journal | vauthors = Satoh M, Kuroiwa T | title = Organization of multiple nucleoids and DNA molecules in mitochondria of a human cell | journal = Experimental Cell Research | volume = 196 | issue = 1 | pages = 137–140 | date = September 1991 | pmid = 1715276 | doi = 10.1016/0014-4827(91)90467-9 }}</ref> with each such molecule normally containing a full set of the mitochondrial genes. Each human mitochondrion contains, on average, approximately 5 such mtDNA molecules.<ref name=Satoh1991/> Each human [[Cell (biology)|cell]] contains approximately 100 mitochondria, giving a total number of mtDNA molecules per human cell of approximately 500.<ref name=Satoh1991/> However, the amount of mitochondria per cell also varies by cell type, and an [[egg cell]] can contain 100,000 mitochondria, corresponding to up to 1,500,000 copies of the mitochondrial genome (constituting up to 90% of the DNA of the cell).<ref name="pmid28721182">{{cite journal | vauthors = Zhang D, Keilty D, Zhang ZF, Chian RC | title = Mitochondria in oocyte aging: current understanding | journal = Facts, Views & Vision in ObGyn | volume = 9 | issue = 1 | pages = 29–38 | date = March 2017 | pmid = 28721182 | pmc = 5506767 }}</ref>