Recent findings suggest that modern humans have inherited DNA from Homo erectus, an ancient species that migrated from Africa over a million years ago, through interbreeding with Denisovans. Researchers utilized protein analysis from ancient teeth, which are more durable than DNA, to uncover this connection. The study focused on Homo erectus teeth samples from three sites in China, dating back approximately 400,000 years. By analyzing the enamel proteins, researchers successfully isolated fragments from both Homo erectus and a Denisovan individual, revealing a genetic link that enhances our understanding of human ancestry and the complex interbreeding patterns that occurred as humans migrated across the globe. This research underscores the significance of proteins in studying ancient species, especially when DNA is no longer viable.