Findings of a new study have suggested that a pair of Egyptian "brother mummies" that were buried next to each other after they died about 4,000 years ago may have been half-brothers and not full siblings.

Manchester Museum's Two Brothers Mummies

The bodies were discovered by a team led by British archaeologist Flinders Petrie at the village of Deir Rifeh south of Cairo in 1907. The mummies were believed to be noblemen who passed away around 1800 BC. Nakht-Ankh is older by at least 20 years, but the younger Khnum-Nakht died six months earlier.

In 1908, archaeologist Margaret Murray found that the skeletal morphology of the bodies was not the same, which suggests the absence of family relationship. Some thought that one of the brothers was adopted albeit there were no scientific evidence to prove this. DNA analyses now show that they only shared a mother, not a father, confirming earlier suspicions.

Different Paternal Lineage

In a study published in the February issue of the Journal of Archaeological Science: Reports, researchers conducted DNA analyses, which confirmed that brothers Khnum-Nakht and Nakht-Ankh have different paternal lines.

The researchers extracted DNA from the molars of the two mummies and then analyzed their mitochondrial DNA, the genetic material passed down from their mother, and the Y chromosomal DNA, which is passed down from their father.

Findings revealed that the two mummies both belong to mitochondrial haplotype M1a1, which show a maternal relationship.

"The two mummies had identical mitochondrial profiles, [so] we can be sure they were related maternally," said study researcher Konstantina Drosou from the Manchester Institute of Biotechnology.

Analysis of the Y chromosome sequences, however, showed variations, which means that Nakht-Ankh and Khnum-Nakht had different paternal lineage.

"The Y chromosome sequences were less complete but showed variations between the two mummies, indicating that Nakht-Ankh and Khnum-Nakht had different fathers," researchers wrote in their study.

"Our study emphasizes the importance of kinship in ancient Egypt, and represents the first successful typing of both mitochondrial and Y chromosomal DNA in Egyptian mummies."

An Ancient Scandal?

It remains unclear if one of the brothers were adopted or if their mother, Khnum-Aa, had an affair. Nonetheless, the study solved one of the mysteries surrounding two of Britain's most famous Egyptian mummies.

"I am very grateful we were able to add a small but very important piece to the big history puzzle and I am sure the brothers would be very proud of us. These moments are what make us believe in ancient DNA," Drosou said.