The picture obtained from this first look at an ancient Egyptian genome is perhaps less groundbreaking than the sequencing of the mummy DNA itself. Analyzing mitochondrial DNA from the 90 mummies and additional genome-wide nuclear DNA from three of them, the researchers found great genetic continuity across the last 33 centuries.
The biggest difference between ancient and modern Egyptians, at least from this small sample, is that modern Egyptians contain eight percent more DNA from sub-Saharan Africa, possibly due to increased trade across the continent, including the slave trade. Because of this admixture of sub-Saharan DNA, the researchers said the ancient Egyptian mummies were genetically more similar to ancient and modern Europeans than modern Egyptians.
Verena Schuenemann, a paleogeneticist from the University of Tübingen and one of the lead authors of the mummy study, said that the best-preserved DNA showed an individual with light skin, dark eyes, and lactose intolerance — a good genetic match with the people of Neolithic Anatolia (modern-day Turkey).
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After being excavated from the Abusir el-Maleq necropolis in 1905, the mummy heads found their way to two German museums. The researchers chose the heads partly because they were the closest mummy parts available, but also because they believed the remains were from everyday ancient Egyptians. The huge burial site at Abusir el-Maleq contains thousands of mummies, not just the big-shots.
“We didn’t want to work on the really high pharaonic elite,” said Schuenemann. “We wanted to do population testing and see how the population structure changed over time. For this, you can’t take only the elite. You have to somehow access the normal people."
Egypt is located at the crossroads of the ancient world, a bridge between the cultures and kingdoms of Northern Africa, the Middle East, the Near East and Europe. The ability to mine ancient genetic data will add new depth to our understanding of how foreign invasions and large-scale migrations influenced the genetic makeup of modern Egyptians. This new study, constrained to less than 100 mummies in one central Egyptian tomb, is just the beginning.
“There are going to be thousands of mummies available for genetic research,” said Schuenemann.
Interestingly, the researchers had the most success extracting DNA from the teeth of the mummies, not the soft tissue, which turns out to contain very little viable DNA. After DNA samples were isolated, Scheunemann and her colleagues had to fish out the ancient human DNA from the DNA of “thousands of different organisms” that lived on and in the mummy teeth — plants, bacteria, fungi.
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They also had to verify the DNA’s age by looking for telltale damage. The less damage, the more likely it was a modern contaminant.
The European researchers then used a series of techniques known collectively as “next-generation” sequencing — a much faster and far more accurate method than PCR — to build up libraries of genomic data. The team didn’t sequence the entire mummy genome. Instead, they focused on isolating and enriching 1.2 million “informative sites” that are most useful in studies of population genetics and carry the best phenotypic information, such as eye color, hair color, and skin pigmentation.
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