By Mindy Weisberger | Live Science
The faces of three men who lived in ancient Egypt more than 2,000 years ago have been brought back to life. Digital reconstructions depict the men at age 25, based on DNA data extracted from their mummified remains.
The mummies came from Abusir el-Meleq, an ancient Egyptian city on a floodplain to the south of Cairo, and they were buried between 1380 B.C. and A.D. 425. Scientists at the Max Planck Institute for the Science of Human History in Tübingen, Germany, sequenced the mummies’ DNA in 2017; it was the first successful reconstruction of an ancient Egyptian mummy’s genome, Live Science reported at the time.
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And now, researchers at Parabon NanoLabs, a DNA technology company in Reston, Virginia, have used that genetic data to create 3D models of the mummies’ faces through a process called forensic DNA phenotyping, which uses genetic analysis to predict the shape of facial features and other aspects of a person’s physical appearance.
“This is the first time comprehensive DNA phenotyping has been performed on human DNA of this age,” Parabon representatives said in a statement. Parabon revealed the mummies’ faces on Sept. 15 at the 32nd International Symposium on Human Identification in Orlando, Florida.
Scientists used a phenotyping method called Snapshot to predict the men’s ancestry, skin colour and facial features. They found that the men had light brown skin with dark eyes and hair; overall, their genetic makeup was closer to that of modern individuals in the Mediterranean or the Middle East than it was to modern Egyptians’, according to the statement.
The researchers then generated 3D meshes outlining the mummies’ facial features, and calculated heat maps to highlight the differences between the three individuals and refine the details of each face. Parabon’s forensic artist then combined these results with Snapshot’s predictions about skin, eye and hair colour.
Working with ancient human DNA can be challenging for two reasons: the DNA is often highly degraded, and it’s usually mixed with bacterial DNA, said Ellen Greytak, Parabon’s director of bioinformatics.
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“Between those two factors, the amount of human DNA available to sequence can be very small,” Greytak told Live Science in an email. However, because the vast majority of DNA is shared between all humans, scientists don’t need the entire genome to glean a physical picture of a person. Rather, they only need to analyse certain specific spots in the genome that differ between people, known as single nucleotide polymorphisms (SNPs). Many of these SNPs code for physical differences between individuals, Greytak said.
However, sometimes ancient DNA doesn’t provide enough SNPs to pinpoint a given trait. In those cases, scientists can replace absent genetic data with substituted values that come from other SNPs nearby, said Janet Cady, a Parabon bioinformatics scientist. Statistics that are calculated from thousands of genomes reveal how closely associated each SNP is with an absent neighbour, Cady told Live Science in an email. From there, the researchers can make a statistical prediction of what the missing SNP was.
The processes used on these ancient mummies could also help scientists to recreate faces to identify modern remains, Greytak told Live Science. Of the approximately 175 cold cases that Parabon researchers have helped to solve using genetic genealogy, so far nine were analysed using the techniques from this study, Greytak said.
This article was originally published by Live Science.