LTR-Retrotransposons from Bdelloid Rotifers Capture Additional ORFs Shared between Highly Diverse Retroelement Types.

Rotifers of the class Bdelloidea, microscopic freshwater invertebrates, possess a highlydiversified repertoire of transposon families, which, however, occupy less than 4% of genomic DNA in the sequenced representative . We performed a comprehensive analysis of retroelements, and found that bdelloid long terminal repeat (LTR)retrotransposons, in addition to conserved open reading frame (ORF) 1 and ORF2 corresponding to and genes, code for an unusually high variety of ORF3 sequences. Retrovirus-like LTR families in belong to four major lineages, three of which are rotiferspecific and encode a dUTPase domain.