Entry for:The Peer Prize for Women in Science 2017
1. Please give a brief summary of your work.
The legend of ancient Egyptian human and animal mummies have been always a source of fascination. There were widespread concerns around the possibility to retrieve aDNA from Egyptian mummies, due to the unfavourable environmental conditions. This study aimed at the recovery of complete mitogenomes from the Egyptian Sacred Ibis mummies using newly developed techniques.
Literally millions of Sacred Ibis mummies, stacked floor to ceiling, in numerous ancient Egyptian catacombs. These birds were mummified as an offering to the God of wisdom, Thoth. The mystery is how were the ancient Egyptians able to collect such extraordinary numbers of these birds? We report the solution to this mystery using an evolutionary analysis of the recovered genomic sequences from these ancient remains and from genomic sequences from birds living across Africa today. These results suggest that the ancient Egyptians may captured seasonally migrating Sacred Ibis, rather than long-term farming of stocks of domesticated birds.
2. Describe your approach and broader findings.
Animal mummies were extremely important to the ancient Egyptian rituals from the 26th Dynasty to the Graeco-Roman Period, where pilgrims offered millions of them to the gods. The majority were for the Sacred Ibis (Threskiornis aethiopicus) that were offered to the God Thoth. Mummified Sacred Ibis specimens were collected from 3 main Ibis burials at Egypt and worldwide museums. We have estimated the radiocarbon ages of Ibis mummies between 2220–2430yr.BP. This study aimed to determine if the Sacred Ibises were farmed for mummification purposes. The recovery of aDNA from ancient Egyptian remains is difficult due to the continued exposure of the remains to the warm and humid climate. We showed that DNA capture methods, in combination with second-generation sequencing, enabled us to recover complete mitochondrial genomes of Sacred Ibis mummies and contemporary samples collected from locations covering the geographic distribution of Sacred Ibis populations across Africa. These samples were used to estimate the genetic diversity of Sacred Ibis across the African continent and this diversity was compared with that of ancient Sacred Ibis populations.
3. What is the wider contribution, or impact, to your scientific field(s)?
Through this research, we proved the feasibility to study ancient Egyptian history through retrieving complete genetic data once stored in the Egyptian remains. The recovery and analysis of ancient DNA (aDNA) from archeological specimens in general, but particularly that from ancient Egyptian remains, has gained increasing attention in the past few decades. Through the genetic testing of human, animal or plant remains, researchers will be able to reveal new insights into evolutionary trails, speciation events and domestication processes. By applying cutting-edge approaches, that is those that rely on target capture and next-generation sequencing, it will allow researchers to investigate ancient Egyptian materials with increased success.
There are numerous ways in which the methodology we used here can be widely used to answer important genetic questions in archaeology. In particular, it will be worthwhile to expand research such further to include human remains and samples from other tropical climates.
4. Are there any potential ideas you would like to explore to take this research further?
In this research, I present proof-of-concept work to demonstrate that ancient Egyptian Sacred Ibis samples preserve mitochondrial DNA at least. However, there are areas of research that were not addressed in this study. This study did not test the preservation of nuclear DNA within the same type of samples, something that should be encouraged for future studies. It is hoped that the results presented herein will encourage more attempts to be made to collect varied specimens from a wide range of animal mummies to estimate the endogenous levels of the nuclear and mitochondrial contents.