Transposable Elements and Their Evolution in Musa

Like other plant species, DNA transposable elements and retrotransposons represent a large fraction of the Musa genome. Mobile elements can be identified 1) by homology to known elements; 2) by characteristic sequence properties such are repeats and short duplications; and 3) by studying their mobility and insertions/deletions in comparisons of homologous or homoeologous chromsome sequences. We have used all three approaches in Musa and I will show results showing the nature of unselected mobile sequences in Musa accessions. Many of the active elements proved to belong to the hAT family of DNA transposons, where there has been limited information on their diversity, abundance and chromosomal localization in plants. Chromosomal in situ hybridization, in silico analysis of genomic sequences, Southern hybridization and biodiversity panels were used to show three major families of the elements in Musa, with some 70 complete autonomous elements, and abundant hAT-related MITEs (Miniature inverted tandem elements).MuhAT transposons and MuhMITEs were localized in subtelomeric, most likely gene-rich regions, of chromosomes. Variation between homologous chromosomes and transduplications of genomic sequences indicate activity of the transposons and suggest a role for the MITEs in modulation of genomic behaviour.

Further details fromwww.molcyt.com; hAt element analysis: Chromosome Research 2015 DOI 10.1007/s10577-014-9445-5.