Evaluation of the current models for the evolution of bacterial DNA uptake signal sequences

Current opinion considers two main hypotheses for the evolutionary origin of uptake signal sequences in bacteria: one model regards the uptake signal sequence (USS) as the result of biased gene conversion, whereas the second model views the USS as a molecular tag that evolved as an adaptation. In this article, we present various computational models that implement specific versions of those hypotheses. Those models show that the two hypothesis are not necessarily as opposed to each other as may appear at first glance.