CNN reports that scientists have created a mouse embryo that's 4% human. The hybrid is what scientists call a human-animal chimera, a single organism that is made up of two different sets of cells. This human-mouse chimera has by far the highest number of human cells ever recorded in an animal.
The team's experiment indicates that there is enough evolutionary compatibility between mice and humans that mouse embryos are a relatively good environment for cultivating human cells. This breakthrough could potentially generate better mouse models to study human diseases, including Covid-19. Mice can also be used to grow human immune cells or respiratory cells.
Future studies could help treat malaria, in which the pathogens specifically infect human red blood cells through a mosquito bite. If scientists can make a mouse with even more human red blood cells, it would be a very good model to study malaria. They could also explore whether this technique could be applied to larger animals, such as pigs, to generate organs for transplants.