Telomeric transposons are pervasive in linear bacterial genomes

Eukaryotes have linear DNA, and their telomeres are hotspots for transposons, which in some cases took over telomere maintenance. We identified several families of independently evolved telomeric transposons in linear chromosomes and plasmids of cyanobacteria and Streptomyces. Although these elements have one specific transposon end sequence, with the second boundary being the telomere, we can show that they move using two transposon ends, likely when transiently bridged by the telomere maintenance systems. Mobilization of the element and the associated telomere allows replacement of native telomeres, making the host cell dependent on the new transposon telomere system for genome maintenance. This work indicates how telomeric transposons can promote gene transfer both between and within genomes, substantially influencing the evolutionary dynamics of linear genomes.