The nucleus has long been seen as the ruler of the cell, packed full of genes that run the show. But the idea it has complete control is questioned by a new study suggesting mitochondria may be able to influence the nucleus.

Mitochondria are energy-generating structures found in the cells of complex organisms which possess their own much smaller genome. Changhan David Lee at the University of Southern California, Los Angeles, and his colleagues have found that in human cells this encodes an RNA that makes a peptide, a protein-like molecule, called …