title: DA and Xiao-two giant and composite LTR-retrotransposon-like elements identified in the human genome.
abstract: We discovered two new complex elements while studying large genomic rearrangements and segmental duplications in the human genome. Both resemble bacterial composite DNA transposon Tn9, consisting of a core flanked by mobile elements, except that the flanking element is not a DNA transposon but instead is long terminal repeat retrotransposon-like with human endogenous retrovirus and satellite sequences. Based on the core size, we named them Xiao ( approximately 30 kb) and DA ( approximately 280 kb), meaning small and big, respectively, in Chinese. Xiao originated from a 19p region encoding olfactory receptor 7E members after the human/ape divergence from Old World monkeys, while DA likely evolved from a Xiao by inserting approximately 200 kb of chimeric sequence from 16p and 21q into the Xiao core, resulting in a target site duplication of 3.4 kb. DA/Xiao was identified in 30 loci on 12 chromosomes, and only DAs mediated intrachromosomal rearrangements, based on our reconstructed human-mouse-rat ancestral genome and the rhesus macaque genome.
authors: Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens, GA 30602-7229, USA.
authors: Xinglai
authors: X
authors: Ji
authors: Shaying
authors: S
authors: Zhao
mesh_terms: D000818:Animals; D001483:Base Sequence; D019457:Chromosome Breakage; D007446:Chromosome Inversion; D004276:DNA, Satellite / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D015321:Gene Rearrangement; D015894:Genome, Human; D006801:Humans; D051379:Mice; D008957:Models, Genetic; D011323:Primates / Q000235:genetics; D051381:Rats; D018626:Retroelements; D013045:Species Specificity; D020079:Terminal Repeat Sequences
chemical_list: D004276:DNA, Satellite; D018626:Retroelements