Internal fragments of the putative transposase gene of mariner-like el
ements (MLEs) were amplified from human, mouse, rat, chinese hamster,
sheep and bovine genomic DNAs by polymerase chain reaction (PCR). The
sequences identified in human, ovine and bovine genomes correspond to
ancient degenerate transposons. Screening mammalian sequence libraries
identified a truncated element in the human ABL gene and the sequence
of its 5'-ITR was determined, This ITR sequences were used in PCR exp
eriments with DNA from six mammalian species and detected full-sized a
nd deleted MLEs. The presence of MLE in mammalian genomes demonstrates
that they are ubiquitous mobile elements found from fungi to man. Thi
s observation strongly raises the possibility that MLE could constitut
e tools for the modification of eucaryotic genomes.