Editing Alu element (section)

{{Short description|Mobile genetic element in the primate genome (including human genome)}}
{{update|date=February 2021}}

An '''Alu element''' is a short stretch of [[DNA]] originally characterized by the action of the ''[[Arthrobacter luteus]] (Alu)'' [[restriction endonuclease]].<ref name=pmid1052772>{{cite journal |doi=10.1016/0092-8674(75)90184-1 |pmid=1052772 |title=Sequence organization of the human genome |journal=Cell |volume=6 |issue=3 |pages=345–58 |year=1975 |last1=Schmid |first1=Carl W |last2=Deininger |first2=Prescott L |s2cid=42804857 }}</ref> ''Alu'' elements are the most abundant [[transposable element]]s in the [[human genome]], present in excess of one million copies.<ref name="pmid9694261">{{cite journal |doi=10.1002/elps.1150190806 |pmid=9694261 |title=Effects of ''Alu'' insertions on gene function |journal=Electrophoresis |volume=19 |issue=8–9 |pages=1260–4 |year=1998 |last1=Szmulewicz |first1=Martin N |last2=Novick |first2=Gabriel E |last3=Herrera |first3=Rene J |s2cid=45917758 }}</ref> Most ''Alu'' elements are thought to be selfish or parasitic DNA. However, it has been suggested that at least some are likely to play a role in evolution and have been used as [[genetic marker]]s.<ref name=pmid11263730>{{cite journal |doi=10.1554/0014-3820(2001)055[0001:ptepda]2.0.co;2 |pmid=11263730 |title=Perspective: Transposable Elements, Parasitic Dna, and Genome Evolution |journal=Evolution |volume=55 |issue=1 |pages=1–24 |year=2001 |last1=Kidwell |first1=Margaret G |last2=Lisch |first2=Damon R |s2cid=25273865 }}</ref><ref name="Pray">{{cite web |last1=Pray |first1=Leslie |title=Functions and Utility of Alu Jumping Genes |url=https://www.nature.com/scitable/topicpage/functions-and-utility-of-alu-jumping-genes-561 |website=Scitable.com |publisher=Nature |access-date=26 June 2019 |date=2008}}</ref>  They are derived from the small cytoplasmic [[7SL RNA]], a component of the [[signal recognition particle]]. ''Alu'' elements are not highly conserved within primate [[genome]]s, as only a minority have retained activity, and originated in the genome of an ancestor of [[Supraprimates]].<ref name=pmid17307271>{{cite journal |doi=10.1016/j.tig.2007.02.002 |pmid=17307271 |title=Evolutionary history of 7SL RNA-derived SINEs in Supraprimates |journal=Trends in Genetics |volume=23 |issue=4 |pages=158–61 |year=2007 |last1=Kriegs |first1=Jan Ole |last2=Churakov |first2=Gennady |last3=Jurka |first3=Jerzy |last4=Brosius |first4=Jürgen |last5=Schmitz |first5=Jürgen }}</ref>

''Alu'' insertions have been implicated in several inherited human diseases and in various forms of cancer.

The study of Alu elements has also been important in elucidating human [[population genetics]] and the [[evolution]] of [[primate]]s, including the [[human evolution|evolution of humans]].

[[File:PLoSBiol3.5.Fig7ChromosomesAluFish.jpg|thumb|300px|[[Karyotype]] from a female human [[lymphocyte]] (46, XX). Chromosomes were hybridized with a probe for Alu elements (green) and counterstained with TOPRO-3 (red). Alu elements were used as a marker for chromosomes and chromosome bands rich in genes.]]