Ancient proteins rewrite rhino family tree

Proteins extracted from the remains of an extinct rhino species (Epiaceratherium itjilik) are among the most ancient ever sequenced. From a sample of enamel from the 23-million-year-old fossil, researchers were able to partially sequence 7 proteins. Integrating these proteins with genome data places Epiaceratherium in a new branch of the rhino family tree — one that split off between 41 million and 25 million years ago. The findings suggest that proteins survive better than researchers thought. This raises the possibility of gleaning molecular insights about evolutionary relationships, biological sex and diet from even older animals — maybe even dinosaurs.