Rotem Sorek

Foreigner or native-born? Your immune system discriminates between them, as do those of bacteria. Yes indeed, bacteria do have immune systems – pretty complex ones at that. And like any useful immune system, the bacterial ones must have a good technique for distinguishing “foreign” from “self.” You may even have heard of the bacterial immune system: It’s called CRISPR, and it’s used in biology research around the world for DNA engineering and genome editing. CRISPR normally inserts short DNA sequences taken from phages – viruses that invade bacteria – into special slots called spacers within…

We were just getting used to the idea of our digestive tract as an ecosystem. There are 10 times as many bacteria in our gut as there are cells in our bodies, and the ecological balance between the different types might affect everything from our tendency to gain weight to our general health and susceptibility to various diseases. Now, a Weizmann Institute researcher has exposed a whole new layer of this ecosystem: the viruses – called phages – that infect our gut bacteria. Dr. Rotem Sorek and his team identified hundreds of these phages in the human gut. They were able to find them thanks to…