A new gene therapy has been shown to reverse some of the effects of ageing in mice and extend their lifespans by up to a quarter. Chinese researchers used CRISPR-Cas9, a powerful gene-editing tool, to inactivate a gene called KAT7, which is a key contributor to cellular ageing. An injection of a viral vector encoded for KAT7 reduced what is known as cellular senescence – the end of cell division ...