<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Burke, William D</style></author><author><style face="normal" font="default" size="100%">Malik, Harmit S</style></author><author><style face="normal" font="default" size="100%">Rich, Stephen M</style></author><author><style face="normal" font="default" size="100%">Eickbush, Thomas H</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Ancient lineages of non-LTR retrotransposons in the primitive eukaryote, Giardia lamblia.</style></title><secondary-title><style face="normal" font="default" size="100%">Mol Biol Evol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Mol. Biol. Evol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Protozoan</style></keyword><keyword><style  face="normal" font="default" size="100%">Evolution, Molecular</style></keyword><keyword><style  face="normal" font="default" size="100%">Giardia lamblia</style></keyword><keyword><style  face="normal" font="default" size="100%">Long Interspersed Nucleotide Elements</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Open Reading Frames</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">Repetitive Sequences, Nucleic Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Homology, Nucleic Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Telomere</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002 May</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">619-30</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Mobile elements that use reverse transcriptase to make new copies of themselves are found in all major lineages of eukaryotes. The non-long terminal repeat (non-LTR) retrotransposons have been suggested to be the oldest of these eukaryotic elements. Phylogenetic analysis of non-LTR elements suggests that they have predominantly undergone vertical transmission, as opposed to the frequent horizontal transmissions found for other mobile elements. One prediction of this vertical model of inheritance is that the oldest lineages of eukaryotes should exclusively harbor the oldest lineages of non-LTR retrotransposons. Here we characterize the non-LTR retrotransposons present in one of the most primitive eukaryotes, the diplomonad Giardia lamblia. Two families of elements were detected in the WB isolate of G. lamblia currently being used for the genome sequencing project. These elements are clearly distinct from all other previously described non-LTR lineages. Phylogenetic analysis indicates that these Genie elements (for Giardia early non-LTR insertion element) are among the oldest known lineages of non-LTR elements consistent with strict vertical descent. Genie elements encode a single open reading frame with a carboxyl terminal endonuclease domain. Genie 1 is site specific, as seven to eight copies are present in a single tandem array of a 771-bp repeat near the telomere of one chromosome. The function of this repeat is not known. One additional, highly divergent, element within the Genie 1 lineage is not located in this tandem array but is near a second telomere. Four different telomere addition sites could be identified within or near the Genie elements on each of these chromosomes. The second lineage of non-LTR elements, Genie 2, is composed of about 10 degenerate copies. Genie 2 elements do not appear to be site specific in their insertion. An unusual aspect of Genie 2 is that all copies contain inverted repeats up to 172 bp in length.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11961096?dopt=Abstract</style></custom1></record></records></xml>