Striking structural dynamism and nucleotide sequence variation of the transposon Galileo in the genome of Drosophila mojavensisReportar como inadecuado

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Mobile DNA

, 4:6

First Online: 04 February 2013Received: 21 September 2012Accepted: 26 November 2012


BackgroundGalileo is a transposable element responsible for the generation of three chromosomal inversions in natural populations of Drosophila buzzatii. Although the most characteristic feature of Galileo is the long internally-repetitive terminal inverted repeats TIRs, which resemble the Drosophila Foldback element, its transposase-coding sequence has led to its classification as a member of the P-element superfamily Class II, subclass 1, TIR order. Furthermore, Galileo has a wide distribution in the genus Drosophila, since it has been found in 6 of the 12 Drosophila sequenced genomes. Among these species, D. mojavensis, the one closest to D. buzzatii, presented the highest diversity in sequence and structure of Galileo elements.

ResultsIn the present work, we carried out a thorough search and annotation of all the Galileo copies present in the D. mojavensis sequenced genome. In our set of 170 Galileo copies we have detected 5 Galileo subfamilies C, D, E, F, and X with different structures ranging from nearly complete, to only 2 TIR or solo TIR copies. Finally, we have explored the structural and length variation of the Galileo copies that point out the relatively frequent rearrangements within and between Galileo elements. Different mechanisms responsible for these rearrangements are discussed.

ConclusionsAlthough Galileo is a transposable element with an ancient history in the D. mojavensis genome, our data indicate a recent transpositional activity. Furthermore, the dynamism in sequence and structure, mainly affecting the TIRs, suggests an active exchange of sequences among the copies. This exchange could lead to new subfamilies of the transposon, which could be crucial for the long-term survival of the element in the genome.

KeywordsTransposable element Drosophila mojavensis Evolution Terminal inverted repeat Phylogeny Genomics AbbreviationsAICAkaike information criterion

AUApproximately unbiased

bpBase pair

BEASTBayesian evolutionary analysis by sampling tree

BIBayesian inference

DDDeletion derivative

DSBDouble-strand break

HTHorizontal transfer

LTTLineage through time

MITEMiniature inverted repeat transposable element

MLMaximum likelihood

NAHRNon-allelic homologous recombination

NCNearly complete

ORFOpen reading frame

TETransposable element

TIRTerminal inverted repeat

TSDTarget site duplication


2RTTwo recombinant TIR elements

2TTwo TIR elements.

Electronic supplementary materialThe online version of this article doi:10.1186-1759-8753-4-6 contains supplementary material, which is available to authorized users.

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Autor: Mar Marzo - Xabier Bello - Marta Puig - Xulio Maside - Alfredo Ruiz


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