Characterization of Tc1 Transposon‐like sequences in Notothenioids

Abstract

The Tc1 family of transposable elements is composed of DNA‐mediated transposons with inverted terminal repeats and an open reading frame encoding a putative transposase. These elements have been identified in a wide range of organisms, among which several fish species. Here we report on the presence of a Tc1‐like element in the ice‐fish Chionodraco hamatus. This element, only 800 bp long, is shorter than those observed so far and contains a degenerate open reading frame of approximately 440 bp bearing several deletions. Corresponding sequences were found in the genomes of other notothenioid species after Southern‐blot hybridization and polymerase chain reaction amplification. Although the efficiency of this widespread Tel element as a phylogenetic marker is still debated, it can be hypothesized that the Tc1‐like family isolated in C. hamatus appeared early in the genome of notothenioids, and its divergence probably accompanied or occurred in parallel to the evolutionary history of this taxon.

Key words:

• Transposon
• Antarctic fish
• Notothenioids