title: The dynamics of mobile promoters: Enhanced stability in promoter regions.
abstract: Mobile promoters are emerging as a new class of mobile genetic elements, first identified by examining prokaryote genome sequences, and more recently confirmed by experimental observations in bacteria. Recent datasets have identified over 40,000 putative mobile promoters in sequenced prokaryote genomes, however only one-third of these are in regions of the genome directly upstream from coding sequences, that is, in promoter regions. The presence of many promoter sequences in non-promoter regions is unexplained. Here we develop a general mathematical model for the dynamics of mobile promoters, extending previous work to capture the dynamics both within and outside promoter regions. From this general model, we apply rigorous model selection techniques to identify which parameters are statistically justified in describing the available mobile promoter data, and find best-fit values of these parameters. Our results suggest that high rates of horizontal gene transfer maintain the population of mobile promoters in promoter regions, and that once established at these sites, mobile promoters are rarely lost, but are commonly copied to other genomic regions. In contrast, mobile promoter copies in non-promoter regions are more numerous and more volatile, experiencing substantially higher rates of duplication, loss and diversification.
authors.affiliation: Applied Mathematics, Western University, London, Ontario, Canada N6A 5B7.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Rabbani
authors.affiliation: Applied Mathematics, Western University, London, Ontario, Canada N6A 5B7. Electronic address: lwahl@uwo.ca.
authors.forename: Lindi M
authors.initials: LM
authors.lastname: Wahl
mesh_terms: D004251:DNA Transposable Elements / Q000235:genetics*; D042822:Genomic Instability; D008957:Models, Genetic; D011401:Promoter Regions, Genetic; D013223:Statistics as Topic
chemical_list: D004251:DNA Transposable Elements
keywords: Horizontal gene transfer; Horizontal regulatory transfer; Microbial evolution; Mobile genetic elements; Statistical model inference