Mice grown with rat brains to help study cross-species organ donation

Hundreds of mouse pups with partial rat brains have been born from embryos made from a mix of mouse and rat cells, marking the first time that the brain of one species has been grown in another from the embryonic stage.

Over the past decade, scientists have been experimenting with growing human organs inside other animals to address the worldwide organ donor shortage. Most recently, Miguel Esteban at Guangzhou Institutes of Biomedicine and Health in China and his colleagues partially grew human …