Molecular characterization and diversity of a novel nonautonomous Mutator-like transposon family in Brassica

Transposable elements (tes) are capable of mobilizing from one genomic location to other,with changes in their copy numbers. mutator-like elements (mules) are dna transposons characterized by 9 bp target site duplications (tsds),with high variability in sequence and length,and include non-conserved terminal inverted repeats (tirs). we identified and characterized a family of mutator-like elements designated as shahroz. the structural and molecular analyses revealed that family had a small number of mostly defective non-autonomous mules and has shown limited activity in the evolutionary history of the brassica a-genome. the shahroz elements range in size from 2734 to 3160 bp including 76 bp imperfect tirs and 9 bp variable tsds. the individual copies have shown high homology (52–99%) in their entire lengths. the study revealed that the elements are less in numbers but active in brassica rapa genomes and pcr amplification revealed their specificity and amplification in a-genome containing diploid and polyploids brassica. the phylogenetic analysis of brassica mules with other plant mutator elements revealed that no correlation exists between brassica mules and other elements suggesting a separate line of evolution. analyzing the regions flanking the insertions revealed that the insertions have showed a preference for at rich regions. the detailed study of these insertions revealed that although less in number and small sizes,they have played a role in brassica genome evolution by their mobilization. © 2015,pakistan botanical society. all rights reserved.