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In this Perspective article, Bernheim and Sorek present the ‘pan-immune system’ model in which bacteria employ horizontal gene transfer to access immune defence mechanisms encoded by closely related strains, and conclude by discussing the implications on the evolution of anti-defence strategies in phages.
The origin of viruses is an unsolved, controversial question. In this Opinion article, Krupovic, Dolja and Koonin propose a new scenario for the origin of viruses based on primordial, selfish replicators acquiring structural proteins from cells, enabling them to form virions.
In this Opinion article, Sonnenburg and Sonnenburg explore whether individuals in the industrialized world may be harbouring a microbial community that is now incompatible with human biology, and they hypothesize that the modern, industrial lifestyle has contributed to alterations in the microbiota that may be linked to the deterioration of human health.
