Editing DNA sequencing (section)

=== Virology ===
{{Main|Virology}}
As most viruses are too small to be seen by a light microscope, sequencing is one of the main tools in virology to identify and study the virus.<ref name=":0c"/> Viral genomes can be based in DNA or RNA. RNA viruses are more time-sensitive for genome sequencing, as they degrade faster in clinical samples.<ref name="Shirlee"/> Traditional [[Sanger sequencing]] and next-generation sequencing are used to sequence viruses in basic and clinical research, as well as for the diagnosis of emerging viral infections, [[molecular epidemiology]] of viral pathogens, and drug-resistance testing. There are more than 2.3 million unique viral sequences in [[GenBank]].<ref name=":0c" /> Recently, NGS has surpassed traditional Sanger as the most popular approach for generating viral genomes.<ref name=":0c">{{cite journal |last1=Castro |first1=Christina |last2=Marine |first2=Rachel |last3=Ramos |first3=Edward |last4=Ng |first4=Terry Fei Fan |title=The effect of variant interference on de novo assembly for viral deep sequencing |journal=BMC Genomics |doi=10.1186/s12864-020-06801-w |biorxiv=10.1101/815480 |year=2019 |volume=21 |issue=1 |page=421 |pmid=32571214 |pmc=7306937 |doi-access=free }}</ref>

During the [[Influenza A virus subtype H5N1#Outbreaks|1997 avian influenza outbreak]], viral sequencing determined that the influenza sub-type originated through [[reassortment]] between [[quail]] and poultry. This led to legislation in [[Hong Kong]] that prohibited selling live quail and poultry together at market. Viral sequencing can also be used to estimate when a viral outbreak began by using a [[molecular clock]] technique.<ref name="Shirlee">{{cite journal|doi=10.1146/annurev-virology-110615-035747|title=Genomic Analysis of Viral Outbreaks|year=2016|last1=Wohl|first1=Shirlee|last2=Schaffner|first2=Stephen F.|last3=Sabeti|first3=Pardis C.|author3-link=Pardis Sabeti|journal=Annual Review of Virology|volume=3|issue=1|pages=173–195|pmid=27501264|pmc=5210220}}</ref>