Editing DNA microarray (section)

{{short description|Collection of microscopic DNA spots attached to a solid surface}}
{{Use dmy dates|date=December 2022}}
[[File:From_spit_to_DNA-sample.webm|thumb|''How to use a microarray for genotyping.'' The video shows the process of extracting genotypes from a human spit sample using microarrays. Genotyping is a major use of DNA microarrays, but with some modifications they can also be used for other purposes such as measurement of gene expression and epigenetic markers.]]

A '''DNA microarray''' (also commonly known as [[DNA]] chip or [[biochip]]) is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA [[microarray]]s to measure the [[Gene expression|expression]] levels of large numbers of genes simultaneously or to [[genotyping|genotype]] multiple regions of a genome. Each DNA spot contains [[Pico-|picomoles]] (10<sup>−12</sup> [[Mole (unit)|moles]]) of a specific DNA sequence, known as ''[[Hybridization probe|probe]]s'' (or ''reporters'' or ''[[oligonucleotide|oligo]]s''). These can be a short section of a [[gene]] or other DNA element that are used to [[Nucleic acid hybridization#Hybridization|hybridize]] a [[cDNA]] or cRNA (also called anti-sense RNA) <!--Agilent kit--> sample (called ''target'') under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of [[fluorophore]]-, silver-, or [[chemiluminescence]]-labeled targets to determine relative abundance of nucleic acid sequences in the target. The original nucleic acid arrays were macro arrays approximately 9&nbsp;cm × 12&nbsp;cm and the first computerized image based analysis was published in 1981.<ref name="Taub">{{cite journal|last1=Taub|first1=Floyd|title=Laboratory methods: Sequential comparative hybridizations analyzed by computerized image processing can identify and quantitate regulated RNAs|journal=DNA|date=1983|volume=2|issue=4|pages=309–327|doi=10.1089/dna.1983.2.309|pmid=6198132}}</ref> It was invented by [[Patrick O. Brown]]. An example of its application is in SNPs arrays for polymorphisms in cardiovascular diseases, cancer, pathogens and GWAS analysis. It is also used for the identification of structural variations and the measurement of gene expression.