Ancient Egyptians believed in the afterlife. For them, death was merely a passage from a temporary body into a permanent spiritual existence. However, the preservation of the physical body was crucial for a happy eternity. The answer: artificial mummification.
It’s a secret
For most of us, the word ‘mummy’ immediately brings to mind images of corpses wrapped in bandages and entombed in a sarcophagus. Actually, Egyptian High Priests developed many methods to achieve this preservation, but they were curiously secretive about their embalming techniques.
Excavations at Hieraconpolis and Adaima in the south of Egypt, place the first mummifications attempts at around 3500 BC, lasting until the Christian Era, going through several alterations and upgrades in the system.
No destruction required
Egyptologists and biologists are not the most obvious combination, but curiosity about the genetic make-up of these mummies quickly led to basic DNA analysis in the 80s. However, the original methods weren’t very reliable and required destruction of valuable mummified tissues.
More recently, biologists have come back to the old problem with a ‘new weapon’: next-generation sequencing (NGS). The NGS techniques involve less invasive procedures, permitting a deeper biological understanding of mummies without causing any damage. In addition, from a technical point of view, these new methods are particularly suited to ancient DNA analysis because they can cope with sequence fragments up to 400 bp in length, which is comparable to that found in degraded ancient genomes.
First time for mummies
Egyptian mummies have never been subjected to NGS- until now. The first step was to determine what kind of information can be obtained from mummified tissues. To do this, a team of researchers from Germany and Egypt, led by Dr Cartsen Pusch, selected five Egyptian mummies (and one dog!) dated from the Third Intermediate to Graeco-Roman mummies (806 BC to 124 AD) and two unearthed Bolivian lowlands skeletons for NGS analysis.
The ability to obtain viable genetic material from mummies has long been the subject of controversy, with many sceptics defending their view that the hot conditions destroy every trace of DNA. However, this study sits on the other side of the fence, as it clearly demonstrated that human DNA was preserved and could be analysed.
Complex embalming recipes
In addition to the obvious human DNA, researchers found a variety of other types of DNA, including plant material clearly associated with embalming ‘recipes’. Analysis supports the idea that castor, linseed, olive and almond oil (as well as fir and pine resins) were used during the embalming process, with populus, garlic and lotus applied possibly to influence the smell of the body.
In addition, scientists got to ‘play doctor’ as they diagnosed mummies with malaria and toxoplasmosis, determined by the presence of Plasmodium falciparum and Toxoplasma gondii DNA sequences. Neither condition came as a surprise, as both carriers for these diseases- royal cats and nuisance mosquitoes – would have been common in Ancient Egypt.
What we can learn?
Following the clues left behind by Egyptian mummies, NGS allows researchers to get a better picture about the embalming procedure, as well as the presence of clinically relevant pathogens, such as bacteria and viruses which may have inflicted ancient populations. According to the authors, “modern NGS technology appears to be a powerful aid to mummy research and strengthens the new discipline of Molecular Egyptology”. Could it be that mysteries concerning the origins of ancient Egyptians, and how they lived and died, can finally be solved?
Rabab Khairat, Markus Ball, Chun-Chi Hsieh Chang, Raffaella Bianucci, Andreas G. Nerlich, Martin Trautmann, Somaia Ismail, Gamila M. L. Shanab, Amr M. Karim, Yehia Z. Gad & Carsten M. Pusch. First insights into the metagenome of Egyptian mummies using next-generation sequencing. 2913. J Appl Genetics. DOI 10.1007/s13353-013-0145-1