In the May 27 SN: Genetic intruders, seeing Chaco in a new light, an artificial womb, Mars’ origin revisited, domestication of the horse, glimpsing Earth’s glacial past, what’s in a fang blenny’s bite and more.
WEAPONS OF MASS EVOLUTION Bacteria and archaea armed with CRISPR systems have been at war with viruses for eons. Here, hordes of viruses known as phages assault a bacterium to turn it into a virus-making factory.
AMI IMAGES/SCIENCE SOURCE
HOT AND COLD Scientists reconstructed three billion years of genetic history for the adenylate kinase enzyme (shown here bound to another molecule) to see how ancient enzymes might have adapted to a cooler Earth.