<P> A transposable element (TE) (also called a transposon or jumping gene) is a mobile segment of DNA that can sometimes pick up a resistance gene and insert it into a plasmid or chromosome, thereby inducing horizontal gene transfer of antibiotic resistance . </P> <P> Horizontal transposon transfer (HTT) refers to the passage of pieces of DNA that are characterized by their ability to move from one locus to another between genomes by means other than parent - to - offspring inheritance . Horizontal gene transfer has long been thought to be crucial to prokaryotic evolution, but there is a growing amount of data showing that HTT is a common and widespread phenomenon in eukaryote evolution as well . On the transposable element side, spreading between genomes via horizontal transfer may be viewed as a strategy to escape purging due to purifying selection, mutational decay and / or host defense mechanisms . </P> <P> HTT can occur with any type of transposable elements, but DNA transposons and LTR retroelements are more likely to be capable of HTT because both have a stable, double - stranded DNA intermediate that is thought to be sturdier than the single - stranded RNA intermediate of non-LTR retroelements, which can be highly degradable . Non-autonomous elements may be less likely to transfer horizontally compared to autonomous elements because they do not encode the proteins required for their own mobilization . The structure of these non-autonomous elements generally consists of an intronless gene encoding a transposase protein, and may or may not have a promoter sequence . Those that do not have promoter sequences encoded within the mobile region rely on adjacent host promoters for expression . Horizontal transfer is thought to play an important role in the TE life cycle . </P> <P> HTT has been shown to occur between species and across continents in both plants and animals (Ivancevic et al. 2013), though some TEs have been shown to more successfully colonize the genomes of certain species over others . Both spatial and taxonomic proximity of species has been proposed to favor HTTs in plants and animals . It is unknown how the density of a population may affect the rate of HTT events within a population, but close proximity due to parasitism and cross contamination due to crowding have been proposed to favor HTT in both plants and animals . Successful transfer of a transposable element requires delivery of DNA from donor to host cell (and to the germ line for multi-cellular organisms), followed by integration into the recipient host genome . Though the actual mechanism for the transportation of TEs from donor cells to host cells is unknown, it is established that naked DNA and RNA can circulate in bodily fluid . Many proposed vectors include arthropods, viruses, freshwater snails (Ivancevic et al. 2013), endosymbiotic bacteria, and intracellular parasitic bacteria . In some cases, even TEs facilitate transport for other TEs . </P>

Can bacteria and archaea transfer genes across species