A pair of ancient Egyptian mummies, known for more than a century as the Two Brothers, turn out to be half-brothers, a new DNA study as found.
The two high-ranking men shared a mother, but had different fathers, say archaeogeneticist Konstantina Drosou of the University of Manchester in England and her colleagues. Thanks to the retrieval of two types of DNA from the mummies’ teeth, the scientists were able to find out their parentage, which lends further evidence to the importance of maternal lines of descent in Ancient Egyptian society.
The mummies of the two men – Khnum-nakht and Nakht-ankh – dated to around 1800 BC, and ever since their discovery in 1907 Egyptologists have argued whether the two were related. In 2015, ‘ancient DNA’ was extracted from their teeth to put an end to the debate.
The half-brothers’ burial site, later dubbed The Tomb of The Two Brothers, was discovered at Deir Rifeh, a village 250 miles south of Cairo. They were found by Egyptian workmen directed by early 20th century colonial Egyptologists, Flinders Petrie and Ernest Mackay.
Hieroglyphic inscriptions on the coffins indicated that both men were the sons of an unnamed local governor and had mothers with the same name, Khnum-aa.
Both mummies are described as sons of an unnamed local governor. It has always been unclear if those inscriptions refer to the same man, but discoverers decided the mummies were full brothers, because the two were buried next to each other and had the same mother.
Over time, skeletal differences discovered between the brothers raised suspicions that they were not biologically related at all, despite the inscriptions, which some researchers argued were misleading.
Adding to those doubts, a 2014 paper reported differences between the two mummies’ mitochondrial DNA, suggesting one or both had no biological link to Khnum-Aa. Mitochondrial DNA typically gets inherited from the mother.
However, Drosou’s team argued that that study extracted ancient DNA from liver and intestinal samples using a method which is commonly susceptible to contamination with modern human and bacterial DNA.
In Drosou’s study, researchers isolated and assembled short pieces of mitochondrial and Y-chromosome DNA from both mummies’ teeth using the latest methods. The Y chromosome determines male sex and gets passed from father to son. This approach minimizes potential contamination from modern sources.
New DNA evidence “proves the hieroglyphic text [on the brothers’ coffins] to be accurate,” at least in confirming the men had the same mother, says study coauthor Campbell Price, curator of the Egypt and Sudan collections at the Manchester Museum in England.
He says that the coffin inscriptions must refer to different fathers who were considered less important family members than the mother, who was named. “Power may have been transferred down the female line rather than simply by a son inheriting [high rank] from his father,” Price suggests. Khnum-Aa’s background, social standing and genetic makeup, however, remain a mystery.
Many written sources from ancient Egypt show precedence to the maternal line, “from the official lists of Egypt’s early kings whose names are accompanied by those of their mothers to nonroyal individuals, who likewise cite only their mother’s name,” Egyptologist Joan Fletcher explains.
Dates of death on the mummies’ linen wrappings suggest that Khnum-Nakht died first, at around age 40, while Nakht-Ankh died at about age 60. The causes of their deaths are unknown.