Friday 12 February 2016

Understanding the Tuli Mummy.

Mummified remains are extremely useful to archaeologists, as they can provide data on both the hard and soft tissues of long-dead individuals. Some ancient cultures, such as the Egyptians and Incas, produced numerous mummified burrials, but in other parts of the world such finds are rare, and generally associated with dry, desicating environments. In Southern Africa a number of such mummies have been reported from caves, rock shelters and other areas water has not been able to reach. The Tuli Mummy was discovered in October 2008 in a grave at the base of a cliff on the Northern Tuli Game Reserve in eastern Botswana. The mummy was wrapped in an cow hide, and was intitially thought to be the remains of an animal burried by poachers; it was therefore partially excavated before the true nature and importance of the find was realized.

In a paper publishd in the South African Journal of Science on 1 February 2016, Frank Rühli of the Institute of Evolutionary Medicine at the University of Zurich, Maryna Steyn of the Forensic Anthropology Research Centre at the University of Pretoria and the School of Anatomical Sciences at the University of the Witwatersrand, Morongwa Mosothwane of the Forensic Anthropology Research Centre at the University of Pretoria and the Archaeology Unit at the University of Botswana, Lena Öhrström, also of the Institute of Evolutionary Medicine at the University of Zurich, Molebogeng Bodiba, also of the Forensic Anthropology Research Centre at the University of Pretoria and Abigail Bouwman, again of the Institute of Evolutionary Medicine at the University of Zurich describe the results of a study of the Tuli Mummy, now housed in the Botswana National Museum, in which the mummy was examined in a CT scanner at the Bokamoso Private Hospital in Gaborone and had DNA extracted at the Archaeology Unit at the University of Botswana then analysed at the Institute of Evolutionary Medicine at the University of Zurich.

 The intact mummy, covered with animal skin, discovered in the Tuli region of Botswana. Rühli et al. (2016).

The Tuli Mummy is a male estimated to have been aged between 40 and 55 years, preserved with skin, nails and hair intact, though part of the right leg was missing, apparently due to scavenging by animals. The body was burried in a foetal possition, with arms and legs folded and the head inclined forwards. Radiocarbon dating of the remains yielded two possible date ranges, between 1675 and 1735 or between 1800 and after 1950, though examination of potshards found with the burrial suggest that the older range is more likely.

While the remains were handled under sterile conditions at the University of Botswana and Botswana National Museum, the initial part of the excavation was carried out under non-sterile conditions, which Rühli et al. acknowledge could be a source of potential contamination, however they hope that the cow hide in which the body was wrapped will have offered a measure of protection, and both bone and soft tissue was removed for DNA analysis.

Not all of the DNA recovered was of usable quality, much being degraded or of apparent bacterial origin, however it was possible to obtain a mitochondrial DNA (mtDNA) sequence, suitable for determining the haplogroup of the mummy (a haplogroup is a group of individuals shown to share a common acestry through the male or female line, using either mitochondrial or Y chromosome DNA). Because mitochondrial DNA is found in the mitochondria, organelles outside the cell nucleus, it is passed directly from mother to child without being sexually recombined each generation, enabling precise estimations of when individuals shared common ancestors, at least through the female line (it is also possible to trace direct ancestry through the male line, using DNA from the Y chromosome, which is passed directly from father to son without sexual recombination).

Analysis of mtDNA from the Tuli Mummy suggests it is a member of the L0 haplogroup, which is found in populations from Southern and East Africa today. The L0 haplogroup is divided into five main branches, thought to have shared a common femal ancestor who lived in East Africa between 150 000 and 170 000 years ago, though the quality of the sequence was not sufficient to assign the sample to any of these subgroups. Comparison of the sequence to other sequences on record showed comparison to a number of sequences donated by Southern Africans, notably a 87% match with a Kgalagadi individual, an 87% match with a Sotho individual, an 86% match with a Tswana and an 86% match with a Zulu (though it should be noted that the sequnce used was quite short.

CT scanning of the remains revealed several bones to be missing, notably the missing part of the right leg, as well as bones from both hands, also likely to have been the result of scavenging. The chest and abdomen of the body were heavly compressed, and the right leg out of position, though this is thought to have been caused after death, probably by animals scavenging the burrial. Several teeth were missing, possibly also having been lost after death. the remaining teeth were extremely worn down, possibly suggesting an older age at time of death than was originally thought, possibly in exess of 50 years.

(a) Three-dimensional volume rendering, (b) maximal intensity projection and (c) sagittal slice of the Tuli mummy. Arrows, soil/stones in cranial and thoracic cavity and pelvis; C, left calcaneal bone; LF, left femoral head; RF, right distal femur in reverse position. Rühli et al. (2016).

Rühli et al.could find no trace of the internal organs of the Tuli Mummy. This may represent a preservational artefact, though this would be hard to explain given the general good preservation of the body, or removal of the internal organs by scavenging animals, though this would be expected to result in far more extensive disruption of the skeleton than was observed. Alternatively the internal organs could have been removed deliberately prior to burrial in order to better preserve the body, as was the case in Ancient Egypt. Rühli et al. note that historical in Zimbabwe rulers deemed sacred were deliberately mummified before burrial, but slowly drying over a low fire, prior to wrapping the body in cloth or the hide of a bull and burried. The removal of internal organs during this process has not previously been recorded, but cannot be ruled out either, and would be consistent with a process of deliberate mummification. 

See also... a 500-year-old Inca child mummy.                                                         In recent years the development of methods for sequencing ancient DNA has led to a greater understanding of how many ancient peoples are related to modern populations, particularly in Europe. However the method has been little used in the Americas, and... the life history of the Egtved Girl.                                                              The ‘Egtved Girl’ was excavated near Egtved... of Leprosy in from an early Anglo Saxon grave from Essex, England.              Leprosy is caused by the Bacterium Mycobacterium leprae; it is fatal, incurable...

Follow Sciency Thoughts on Facebook.