Editing DNA extraction (section)

==Special types ==
Specific techniques must be chosen for the isolation of DNA from some samples. Typical samples with complicated DNA isolation are:
* archaeological samples containing partially degraded DNA, see [[ancient DNA]]<ref>{{cite journal | vauthors = Pääbo S | title = Ancient DNA: extraction, characterization, molecular cloning, and enzymatic amplification | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 86 | issue = 6 | pages = 1939–43 | date = March 1989 | pmid = 2928314 | doi = 10.1073/pnas.86.6.1939 | bibcode = 1989PNAS...86.1939P | pmc = 286820 | doi-access = free }}</ref>
* samples containing inhibitors of subsequent analysis procedures, most notably inhibitors of [[Polymerase chain reaction|PCR]], such as [[humic acid]] from the soil, [[indigo]] and other fabric dyes or [[haemoglobin]] in blood
* samples from microorganisms with thick cellular walls, for example, [[yeast]]
*samples containing mixed DNA from multiple sources

Extrachromosomal DNA is generally easy to isolate, especially [[plasmid]]s may be easily isolated by cell lysis followed by precipitation of proteins, which traps chromosomal DNA in insoluble fraction and after centrifugation, plasmid DNA can be purified from soluble fraction.

A Hirt DNA Extraction is an isolation of all [[extrachromosomal DNA]] in a mammalian cell. The Hirt extraction process gets rid of the high molecular weight [[nuclear DNA]], leaving only low molecular weight [[mitochondrial DNA]] and any viral [[episomes]] present in the cell.