Zaba: A novel miniature transposable element present in genomes of legume plants

Abstract

A novel family of miniature transposable elements, named Zaba, was identified in pea (Pisum sativum) and subsequently also in other legume species using computer analysis of their DNA sequences. Zaba elements are 141-190 bp long, generate 10-bp target site duplications, and their terminal inverted repeats make up most of the sequence. Zaba elements thus resemble class 3 foldback transposons. The elements are only moderately repetitive in pea (tens to hundreds copies per haploid genome), but they are present in up to thousands of copies in the genomes of several Medicago and Vicia species. More detailed analysis of the elements from pea, including isolation of new sequences from a genomic library, revealed that a fraction of these elements are truncated, and that their last transposition probably did not occur recently. A search for Zaba sequences in EST databases showed that at least some elements are transcribed, most probably due to their association with genic regions.