Worm Breeder's Gazette 10(2): 142
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
Transposable elements, like Tc1, have a much wider phylogenetic distribution than previously thought. Tc1 and TCb1 (also known as Barney) share sequence identity with the open reading frame (ORF) of the HB elements found in Drosophila melanogaster. The ORFs of Tc1 and Barney can be aligned with HB1 after the introduction of 3 centrally located deletions in HB1. These reading frames would code for proteins with 30% amino acid identity (42% when conservative changes are included). Tc1, Barney and HB1 contain highly conserved blocks of amino acids which are likely to be in the functional domains of the putative transposase. It is unfortunate that the HB elements in Drosophila are defective and can't reveal secrets of mobility. Within the class of inverted repeat elements, a subclass of closely related elements exists. This subclass includes Tc1 and Barney in the Nematoda and HB in Arthropoda. Since these phyla are evolutionarily quite distant it is reasonable to suppose that Tc1-like elements will have a wide distribution within the eukaryotes. Their presence in these two phyla could have resulted from the existence of the element in a common ancestor prior to the time of divergence (>500 million years) or might have resulted from more recent horizontal transfer. The sequence comparisons of Tc1, Barney and HB1 are to be published in Nucleic Acids Research.