The evolution of tyrosine-recombinase elements in Nematoda Amir Szitenberg1, Georgios Koutsovoulos2, Mark L Blaxter2 and David H Lunt1 1Evolutionary Biology Group, School of Biological, Biomedical & Environmental Sciences, University of Hull, Hull, HU6 7RX, UK 2Institute of Evolutionary Biology, The University of Edinburgh, EH9 3JT, UK
[email protected] Abstract phylogenetically-based classification scheme. Nematode Transposable elements can be categorised into DNA and model species do not represent the diversity of RNA elements based on their mechanism of transposable elements in the phylum. transposition. Tyrosine recombinase elements (YREs) are relatively rare and poorly understood, despite Keywords: Nematoda; DIRS; PAT; transposable sharing characteristics with both DNA and RNA elements; phylogenetic classification; homoplasy; elements. Previously, the Nematoda have been reported to have a substantially different diversity of YREs compared to other animal phyla: the Dirs1-like YRE retrotransposon was encountered in most animal phyla Introduction but not in Nematoda, and a unique Pat1-like YRE retrotransposon has only been recorded from Nematoda. Transposable elements We explored the diversity of YREs in Nematoda by Transposable elements (TE) are mobile genetic elements sampling broadly across the phylum and including 34 capable of propagating within a genome and potentially genomes representing the three classes within transferring horizontally between organisms Nematoda. We developed a method to isolate and (Nakayashiki 2011). They typically constitute significant classify YREs based on both feature organization and proportions of bilaterian genomes, comprising 45% of phylogenetic relationships in an open and reproducible the human genome (Lander et al. 2001), 22% of the workflow. We also ensured that our phylogenetic Drosophila melanogaster genome (Kapitonov and Jurka approach to YRE classification identified truncated and 2003) and 12% of the Caenorhabditis elegans genome degenerate elements, informatively increasing the (Bessereau 2006).