THE POTENTIAL OF DNA TECHNIQUES WITH ANCIENT EGYPTIANS MUMMIES

May 6, 2011

THE POTENTIAL OF DNA TECHNIQUES WITH ANCIENT EGYPTIANS MUMMIES

Until the 1970s, when the Swedish scientist Svante Pääbo pioneered techniques that have been subsequently refined to identify DNA in mummies, the only method with the potential to trace familial relationships or population movements, or to identify the present-day descendants of ancient peoples was paleoserol ogy, the study of blood groups in ancient human remains. Since the 1930s, several studies had been carried out to identify blood groups in ancient human remains, and some success was demonstrated with the serological micromethod (SMM) and the inhibition agglutination test (IAT).


Since blood-group substances (ABO) exist not only in the blood but also in muscle, skin, and brain, there was the possibility of extracting this information even from dehydrated ancient tissues; however, there were considerable problems with the techniques. Contaminants such as microorganisms present within the tissue itself or even the various substances used in the mummification process can appear to react as blood groups and therefore produce false positive reactions. Also, a substance found in fresh samples may deteriorate over time and become undetectable in ancient samples, producing a false or unreliable result. Nevertheless, one such significant study to prove kinship was undertaken on the mummies of Tutankhamun and of the body found in Tomb 55 in the Valley of the Kings.
The tests indicated that they shared the same blood group; however, since paleoserology poses such difficulties, it has largely been replaced by DNA analysis.
DNA procedures have opened up possibilities not only of establishing familial relation-ships and population origins and migrations, but also of expanding our knowledge of disease in the mummies. Scientists are now trying to identify bacterial and viral DNA in mummies, and this could confirm the presence of some infectious diseases in ancient individuals and populations that existing techniques cannot currently detect.
Another line of investigation has been attempting to identify the DNA of disease-producing parasites within the human host; in 2002, the Manchester Mummy Project team succeeded in isolating the DNA of a schistosome, the parasite that causes the disease schistosomiasis.
Since the total genetic information of any living organism is carried in almost every cell of the body, only a small sample of bone or tissue is required for DNA identification; how-ever, considerable problems are encountered in obtaining suitable samples from ancient remains, particularly because of the possibility of contamination of the specimens.Egyptian King Tut Coffin (Gpp) - Collectible Figurine Statue Sculpture
In the earliest DNA studies, laborious cloning and sequence reading strategies were required to analyze the specimens. More recently, polymerase chain reaction (PCR), also known as “gene amplification,” is a quicker and more effective technique used for DNA studies on ancient material. And further developments in this field can be expected as an increasing number of DNA projects are being under-taken on newly excavated samples and on mummies in existing collections.

THE EPIDEMIOLOGICAL APPROACH

Until the mid-1990s, research on mummified remains had concentrated on in-depth investigations of individual mummies or broader studies of large numbers of bodies, as in the Archaeological Survey of Nubia. In 1995, a new approach was adopted when it was decided to establish a collaborative study among the Manchester Egyptian Mummy Project, in England; the Medical Service Corporation International (MSCI), based in Arlington, Virginia; and the Egyptian Organization for Biological Products and Vaccines (VACSERA), in Cairo. The aim of this study was to construct an epidemiologic profile of schistosomiasis (also known as bilharziasis) in Egypt in the period between the twenty-sixth century BC and the seventh century AD, and then compare those results with data that have been collected in a modern epidemiologic study in Egypt.

Today, schistosomiasis, a chronic and debilitating disease, affects up to 300 million people in many tropical and subtropical parts of the world. It is caused by a parasite known as a schistosome. In order to complete its life cycle, the schistosome requires the presence of both a human host and a water snail. It is therefore found in countries where some of the population have regular and frequent access to snail-infected, stagnant stretches of water. In recent years, water development programs such as dam construction and irrigation systems have accelerated the problem by creating new breeding sites for the snails.
The disease has a major impact on an agricultural workforce and on national economic productivity. Although drugs can cure the disease, people’s lifestyle usually remains unchanged, and so they frequently become reinfected. Today, there are several programs attempting to develop a vaccine against schistosomiasis.
A ten-year research program, the Schisto-somiasis Research Project, was set up and undertaken in Egypt in 1988. Funded by the government of Egypt and the U.S. Agency for International Development, it had the objectives of identifying the current epidemiologic patterns of schistosomiasis and developing better methods of preventing, diagnosing, and treating the disease. When the modern-day research first went under way, 20 percent of the population of Egypt was thought to be infected with the disease, and in some villages, the prevalence rates were more than 85 percent. The Schistosomiasis Research Project collected infection data on more than
100,000 people from villages between the Nile Delta in the north and Aswan, located in the south of the country.

Comparisons will eventually be drawn between this data and the incidence patterns in ancient times to describe the disease patterns and evolution of schistosomiasis in Egypt over a 5,000-year period.

Regarding the historic side of this project, there has been considerable scholarly debate about whether the ancient Egyptians actually diagnosed and recorded schistosomiasis.
In the ancient medical papyri, there are many references to “worms,” and one affliction termed the disease is recorded fifty times. The texts mention the presence of hematuria (blood in the urine) in association with this disease. This is a classic symptom of one form of schistosomiasis in which a specific parasite (Schistosome haemato-bium) infects the patient and affects the bladder; thus, some Egyptologists have regarded these references as clear identifications and descriptions of this type of the disease.
This symptom is however also found in other types of parasitic infection, and other scholars have claimed that the papyri describe more generalized parasitic conditions. They consider that the Egyptians almost certainly would not have performed autopsies within a short enough time span and in sufficient detail to have been able to discover this specific schistosome.
Also, it probably would not have been visible to the naked eye; in modern times, the German scientist Theodor Bilharz used a microscope to become the first person to identify and describe the parasite in 1852.
There is evidence, nonetheless, in Egyptian mummified remains that schistosomiasis existed in antiquity.
In 1910, the paleopathologist Ruffer reported that he had observed the calcified eggs of Bilharzia haematobia in the kidneys of two mummies dating to c.1100 BC, and eggs have been discovered in mummies of other periods. A range of diagnostic techniques have been used to detect the disease in mummies.
These have included noninvasive X-ray examination of mummies to identify the classic pathological calcifications that are secondary results of chronic schistosomiasis in the liver (Schistosoma mansoni) and in the kidneys and bladder (Schistosoma haematobium), and direct microscopic examination of rehydrated mummified tissue to detect the presence and con- firm the species of eggs.
Another method, the immunological analysis of tissue or bone samples using the enzyme-linked immunosorbent assay (ELISA), has been used to detect the presence of circulating anodic antigen, a glycoprotein regurgitated from the gut of the schistosome. (In live patients, its presence is used diagnostically to indicate that the disease is present and that there is an active infection.
Its detection in a mummy shows that the person was suffering from an active infection at the time of death.)
However, for the Manchester team’s research on ancient Egyptians for the schistosomiasis project, it was decided that two new approaches were required: the establishment of an international tissue bank and the development of a new diagnostic tool.

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