The fossil, now dubbed Xujiayao 11, is just one of many examples of ancient human remains that display rare or unknown congenital abnormalities, according to the researchers. “These populations were probably relatively isolated, very small and, as a consequence, fairly inbred,” study leader Erik Trinkhaus, an anthropologist at Washington University in St. Louis, told LiveScience.
The human skull fossil has a hole at its top, a disorder known as an “enlarged parietal foramen,” which matches a modern human condition of the same name caused by a rare genetic mutation. The genetic abnormalities obstruct bone formation by preventing small holes in the prenatal braincase from closing, a process that normally occurs within the first five months of the fetus’ development. Today, these mutations are rare, occurring in only about one of every 25,000 human births.
Story: Tanya Lewis | Photo: Erik Trinkaus/WUSTL