Impact of Ty3/Gypsy group retrotransposon Lila on the D-Genome specificity of common wheat Triticum aestivum L

An analysis of the primary structure of BAC clone 112D20 T. aestivum , that contains D-genome specific Ty3- Gypsy -retrotransposon Lila is presented. PCR analysis of nulli-tetrasomic and deletion lines of T. aestivum allowed to localize this BAC clone in the distal region of the long arm of chromosome 5D. Characteristic feature of BAC clone 112D20 is a high concentration of Ty3- Gypsy -retrotransposons (61.7%), and low content of the genes (1.2%). Only a single open reading frame was revealed homologous to an unknown gene of Ae. tauschii . Specific to the D-genome Ty3- Gypsy -retrotransposon Lila in the BAC clone 112D20 is 14 kb in length and contains unequal in size long terminal repeats. The data of in situ hybridization and PCR analysis of different Triticeae species suggest that this retroelement was amplified within the ancestral species of Ae. tauschii , the donor D-genome. The suggested time of amplification based on estimation of insertion time of Lila 112D20 is 1.7 million years, which corresponds to the formation of the first allopolyploid forms of wheat. Based on comparison with the previously obtained data, it is concluded that the amplification of retroelements specific to each genome of wheat took place during formation of the diploid progenitors of these genomes.