The genes were injected during the mouse’s embryonic state and created a chimera, which is the term for an animal that sports two distinct sets of DNA.

Scientists have engineered a hybrid mouse with a gene that predates all animal life. The team replaced a single gene in the mouse stem cells with a version from an ancient, single-celled ancestor ...

The emergence of Sox and POU transcription factors predates the origins of animal stem cells. Nature Communications, 2024; 15 (1) DOI: 10.1038/s41467-024-54152-x ...

The wildtype mouse on the right has red eyes and all white fur. The colour difference is due to genetic markers used to distinguish the stem cells, not a direct effect of the gene itself.