The Juan non-LTR retrotransposon in mosquitoes: genomic impact, vertical transmission and indications of recent and wide-spread activity

Biedler, James K.; Tu, Zhijian Jake

The Juan non-LTR retrotransposon in mosquitoes: genomic impact, vertical transmission and indications of recent and wide-spread activity

dc.contributor.author	Biedler, James K.	en
dc.contributor.author	Tu, Zhijian Jake	en
dc.contributor.department	Biochemistry	en
dc.date.accessioned	2012-08-24T12:12:08Z	en
dc.date.available	2012-08-24T12:12:08Z	en
dc.date.issued	2007-07-09	en
dc.date.updated	2012-08-24T12:12:08Z	en
dc.description.abstract	Background In contrast to DNA-mediated transposable elements (TEs), retrotransposons, particularly non-long terminal repeat retrotransposons (non-LTRs), are generally considered to have a much lower propensity towards horizontal transfer. Detailed studies on site-specific non-LTR families have demonstrated strict vertical transmission. More studies are needed with non-site-specific non-LTR families to determine whether strict vertical transmission is a phenomenon related to site specificity or a more general characteristic of all non-LTRs. Juan is a Jockey clade non-LTR retrotransposon first discovered in mosquitoes that is widely distributed in the mosquito family Culicidae. Being a non-site specific non-LTR, Juan offers an opportunity to further investigate the hypothesis that non-LTRs are genomic elements that are primarily vertically transmitted. Results Systematic analysis of the ~1.3 Gbp Aedes aegypti (Ae. aegypti) genome sequence suggests that Juan-A is the only Juan-type non-LTR in Aedes aegypti. Juan-A is highly reiterated and comprises approximately 3% of the genome. Using minimum cutoffs of 90% length and 70% nucleotide (nt) identity, 663 copies were found by BLAST using the published Juan-A sequence as the query. All 663 copies are at least 95% identical to Juan-A, while 378 of these copies are 99% identical to Juan-A, indicating that the Juan-A family has been transposing recently in evolutionary history. Using the 0.34 Kb 5' UTR as the query, over 2000 copies were identified that may contain internal promoters, leading to questions on the genomic impact of Juan-A. Juan sequences were obtained by PCR, library screening, and database searches for 18 mosquito species of six genera including Aedes, Ochlerotatus, Psorophora, Culex, Deinocerites, and Wyeomyia. Comparison of host and Juan phylogenies shows overall congruence with few exceptions. Conclusion Juan-A is a major genomic component in Ae. aegypti and it has been retrotransposing recently in evolutionary history. There are also indications that Juan has been recently active in a wide range of mosquito species. Furthermore, our research demonstrates that a Jockey clade non-LTR without target site-specificity has been sustained by vertical transmission in the mosquito family. These results strengthen the argument that non-LTRs tend to be genomic elements capable of persistence by vertical descent over a long evolutionary time.	en
dc.description.version	Published version	en
dc.format.mimetype	application/pdf	en
dc.identifier.citation	BMC Evolutionary Biology. 2007 Jul 09;7(1):112	en
dc.identifier.doi	https://doi.org/10.1186/1471-2148-7-112	en
dc.identifier.uri	http://hdl.handle.net/10919/18927	en
dc.language.iso	en	en
dc.rights	Creative Commons Attribution 4.0 International	en
dc.rights.holder	James K Biedler et al.; licensee BioMed Central Ltd.	en
dc.rights.uri	http://creativecommons.org/licenses/by/4.0/	en
dc.title	The Juan non-LTR retrotransposon in mosquitoes: genomic impact, vertical transmission and indications of recent and wide-spread activity	en
dc.title.serial	BMC Evolutionary Biology	en
dc.type	Article - Refereed	en
dc.type.dcmitype	Text	en