Evolution of DNA Uptake Signal Sequences

Abstract

The DNA of some naturally competent species of bacteria contains a large number of evenly distributed copies of a short sequence. This highly overrepresented sequence is believed to be an uptake signal sequence (USS) that helps bacteria to take up DNA selectively from (dead) members of their own species. For some time it has been assumed that the USS evolved in order to enable bacteria to distinguish between conspecific and nonconspecific DNA fragments (the preference-first hypothesis). Recently, Redfield suggested that this hypothesis is not in fact realistic, as it would require biologically implausible group selection. In this article we present a model designed to demonstrate the emergence of similar USSs in a population of simulated evolving agents. We use this model to examine the conditions under which a USS will emerge in a preference-first scenario.