Abstract
Tc1 / mariner transposons found in salmoniform fish have been identified in both closely and distantly related fish species, suggesting that horizontal gene transfer may have occurred. However, the vectors of this process remain unknown. We identified two homologous sequences in the parasitic nematode Anisakis simplex , naming them Tas1 ( T ransposable element of A nisakis s implex number 1 ) and Tas2 . These elements encode Tc1 / mariner transposases structurally similar to the active Sleeping Beauty transposase. Furthermore, Tas1 / 2 were also identified in organisms that serve as hosts for Anisakis . These findings suggest that Tas1 / 2 may have undergone horizontal gene transfer within host-parasite interactions.