Identification and structural characterization of further DNA elements in the potato and pepper genomes homologous to the transposable element-like insertion Tst1

Characterization of the Sol3 family of nonautonomous transposable elements in tomato and potato

Sol3 transposons are mobile elements defined by long terminal inverted repeats which are found in tomato and potato. Members of the Sol3 family have been isolated from a variety of solanaceous species including Solanum tuberosum (potato), S. demissum, S. chacoense, Lycopersicon esculentum (tomato), and L. hirsutum. While highly conserved elements are found within different species, Sol3 terminal inverted repeats can also flank unrelated sequences. Southern blot analysis indicates that Sol3 elements are less prevalent in the potato (approximately 50 copies) than in the tomato (>100 copies) genome. No Sol3-hybridizing sequences were observed in tobacco. While a number of Sol3 elements ranging in size from 500 bp to 2 kbp were sequenced, no transposase coding domains could be identified within the internal regions of the elements. The data suggest that the Sol3 represent a heterogeneous family of nonautonomous transposable elements associated with an as-yet-unidentified autonomous transposon.

Genomic sequences with homology to the P element of Drosophila melanogaster occur in the blowfly Lucilia cuprina

We have cloned two DNA elements (Lu-P1 and Lu-P2) from the Australian sheep blowfly Lucilia cuprina that are similar to the transposable P element of Drosophila melanogaster in both structure and sequence but have diverged from it and from each other considerably. Hybridization studies indicate that a third related element probably exists in another, as yet unsequenced, clone. Neither Lu-P1 nor Lu-P2 appears to be active in terms of mobility, and it is not known whether any transposition-competent copies of other related elements occur in the genome of the blowfly. However, the isolation of any P-like sequences from a species outside of the family Drosophilidae allows comparisons to be made of more widely divergent P-related elements than has been possible previously. We are unaware of any report of the presence of multiple P-like family members within a single species. The discovery of Lu-P1 and Lu-P2 in the blowfly fuels the possibility that similar elements may be widespread in insects, and perhaps in other orders of animals.