Retrolyc1-1, a member of the Tnt1 retrotransposon super-family in the Lycopersicon peruvianum genome

Retrotransposons are ubiquitous mobile genetic elements that transpose thro ugh an RNA intermediate. One of the best known plant retrotransposon, Tnt1, was isolated from tobacco and showed an extensive distribution in the Nico tiana genus. We investigated the presence of related sequences in the Lycop ersicon genus, another member of the Solanaceae family. Hybridization exper iments performed using Tnt1 probes indicated that homologous sequences were present in all Lycopersicon species, indicating that these Tnt1-related se quences, that we named Retrolyc1, are distributed throughout the Lycopersic on genus. Different distribution patterns were detected between species, de monstrating a potential use of Retrolyc1 elements as molecular markers. An incomplete Retrolyc1 sequence, that we named Retrolyc1-1, was isolated from an L. peruvianum genomic library. Retrolyc1-1 shows extensive homology wit h Tnt1 sequences except in the LTR U3 region. Since this region is known to be involved in the control of transcription, this strongly suggests the ex istence of different patterns of regulation for Tnt1 and Retrolyc1 elements . The study of these two elements within the Solanaceae family may provide interesting models for retrotransposon evolution within this group and tran smission in host genomes.