Speaker
Description
While independently replicating sequences, such as transposons, are common in bacterial genomes, they usually do not persist for long periods of time. To be maintained in the gene pool bacterial mobile genetic elements require to jump hosts. In contrast, short sequence repeats known as REPINs – whose replication is dependent on a non-jumping RAYT transposase – persist for millions of years in bacterial genomes, in the absence of horizontal transfer. Extremely long persistence times and confinement to a single genome makes REPIN populations unique in biology. REPINs duplicate magnitudes less frequently than transposons, which means duplication events cannot be observed in the laboratory. Yet, across different bacterial strains REPIN population biology can be studied. For example, population size fluctuations correlate with available genome space as expected for organisms growing to carrying capacity. Other analyses of REPIN populations within species demonstrate signs of conflict between host and REPINs and how these conflicts are settled. Finally, a search for similar kinds of biological entities suggests that the REPIN-RAYT system may not be unique in bacteria.
