A mystery surrounding the parentage of two 4000-year-old mummies has finally been solved—using cutting-edge DNA sequencing. The mummies’ tomb was found undisturbed in 1907, and they became known as the “two brothers” as hieroglyphics on both coffins referred to the same mother. However, differences in the men’s skeletal structure put their fraternal relationship in doubt. Now, by comparing DNA sequences extracted from the teeth of each mummy, researchers have concluded that two men were just half-brothers, Science News reports. Writing in the Journal of Archaeological Science: Reports, the authors say that the coburial of two siblings who share a mother adds to the evidence that ancient Egyptians gave precedence to the maternal line.