Editing Gene duplication (section)

===Ectopic recombination===
Duplications arise from an event termed [[unequal crossing-over]] that occurs during meiosis between misaligned homologous chromosomes. The chance of it happening is a function of the degree of sharing of repetitive elements between two chromosomes. The products of this recombination are a duplication at the site of the exchange and a reciprocal deletion. Ectopic recombination is typically mediated by sequence similarity at the duplicate breakpoints, which form direct repeats.  Repetitive genetic elements such as [[transposable]] elements offer one source of repetitive DNA that can facilitate recombination, and they are often found at duplication breakpoints in plants and mammals.<ref>{{cite web |title=Definition of Gene duplication |date=2012-03-19 |work=medterms medical dictionary |publisher=MedicineNet |url=http://www.medterms.com/script/main/art.asp?articlekey=3562 |access-date=2008-12-01 |archive-date=2014-03-06 |archive-url=https://web.archive.org/web/20140306214736/http://www.medterms.com/script/main/art.asp?articlekey=3562 |url-status=dead }}</ref>
[[Image:gene-duplication.png|thumb|200px|Schematic of a region of a chromosome before and after a duplication event]]