Isolation from the horse genome of a new DNA transposon belonging to the Tigger family.

Tigger elements are human DNA transposons homologous to the pogo element of Drosophila melanogaster. They contain an open reading frame for a transposase very similar to the major mammalian centromere protein CENP-B. We found in the horse genome a DNA element ( Ecatig3) sharing 88% homology with human Tigger3. The presence of Tigger elements in the horse genome confirms previous data that date these elements before the divergence between Perissodactyla and Primates (80-90 Myr ago). Copy number evaluation indicates that the horse element is much more abundant than its human counterpart. Southern blot analysis demonstrates that Ecatig3 elements are extremely homogeneous; this may indicate that the evolution of this DNA transposon has been driven by some kind of selection and has not been neutral.