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Tools of Discovering African History: Bio-archaeology

Over the years as humans continue to advance, making new discoveries in science, technological breakthroughs, and other new modern findings. Inevitably these achievements have had a profound effect on the ways and methods of man’s search to uncover his origins, Particularly in bioarchaeology; from the times of sociocultural anthropology methods to cranial suture ossification to more advanced methods like stable isotope analyses to even more advanced present-day methods like human genome sequencing.

Seeking knowledge about the human past often involves the studying of the remains of ancient individuals, this unavoidably will involve the application of various methods and tools of archaeology to arrive at a correct and accurate conclusion.

This article discusses some of the popular methods or tools that are employed which aids in determining not only ancient African ancestry but also offers valuable information on ancient humans as well.

STABLE ISOTOPE ANALYSES

The use of isotope analyses in archaeology cannot be overestimated; it has proved invaluable in the study of history and is among the best method that helps to determine the origin of ancient people through diet.

Stable isotope analyses is basically what the name says it is; the analysis of isotopic signatures of stable isotopes within a chemical compound.

Bioarchaeologists can carry out stable isoptope analyses of nitrogen and carbon in the human bone to reveal dietary reconstruction and deduce nutritional inferences. This is because food leaves isotopic markers in the bones and teeth, researchers through isotopic analyses identify the isotopic markers of these foods which helps them reconstruct the diet.

Isotopes imbue humans during their lifespan through eating, drinking, and inhalation of particles, these isotopes upon the death of an individual cease to accumulate, however, because isotopes undergo degradation, it is important for the archaeologist to have an idea of the time of death to allow for a more accurate result.

During archaeological excavation, the paleontologist encounters bones or bone pieces/fragments of humans. These bones and teeth through isotopic analyses can provide information about the diet of the owner, in scientific terms known as palaeodiet, which makes it possible for archaeologists to even predict the migration pattern of the individual when they were alive if any.

While considering the effect of diagenesis which can disturb original isotopic signal, data from the nitrogen and carbon compositions in the bone give information on the possible diet while the oxygen isotopes provide data that is useful to determine geographic location.

MACROSCOPY AND MICROSCOPY

This is another useful tool in the field of bioarchaeology. It involves a close examination of the skeletal remains of humans. This process alone cannot be used to arrive at a conclusion; it serves rather a supportive role. The human bone is susceptible to stress during its lifetime which can alter its shape, size, development, and even consistency, these most times offer clues that when combined with other examinations or analyses helps to more strongly affirm a conclusion.

A Microscope

Applying Microscopy, the bones are closely scrutinized to look for abnormalities and even offer an insight as to the cause of death, or ancient medical/surgical attempts at treatment.

For example, a close examination of the skeleton of Cro‐Magnon men at Padina and Hajducka Vodenica in the Djerdap gorge, showed that it appeared normal but for some slight ridges and bony excrescences on their jaws. For some time these findings were presumed to be insignificant until further research established that the abnormality was probably caused by protracted chewing of grass and plants in order to sustain a diet lacking in meat(Zivanovic S. Ancient disease: the elements of palaeopathology. London: Methuen, 1982).

Macroscopy can be used to determine gender, ethnicity, age, and even population numbers. Because macroscopy can be used to determine age, it can lead to the establishment of the percentage of children, youths, mature adults and old people which in turn leads to the determination of infant mortality rates and life expectancy.

Microscopy, when applied, can give vital information on the effect of diseases on ancient civilization. The scanning electron microscope(SEM) can be used to identify large organic molecules, blood cells and pieces of chromosomal matter which can be further examined. The SEM has also been very useful in unveiling detailed structure of relics that hitherto has been partly damaged. Microscopy can be used in determining whether pieces of isolated bones originated from a single source or from different individuals.

IMAGING

Human remains when examined using non-destructive radiography can reveal much information. Radiography rather than macroscopy is preferred in determining the full extent of skeletal conditions. It can also be used to determine, gender, age, and blood relationships. Radiographs can be used to determine dietary deficiencies, childhood diseases and also Harris lines, Harris lines are produced in bones when they undergo stress over a length of time and can further reveal information like the number of births by an adult female.

A Mummy about to undergo a CT Scan

Computer-assisted tomography(CT) can be used to scan a coffin to compare its contents with the inscriptions on it; this process gives archaeologists an idea of the contents of the coffin before it is opened which minimizes or prevents damage both to the remains and other contents of the coffin.

Endoscopy is another method of imaging. It involves the use of a narrow tube containing a camera that is inserted through a small hole in other to access areas that hitherto would have been inaccessible. The camera transmits live images, which aids archaeologists make informed decisions.

BIOCHEMICAL ANALYSES

Chemical and toxicological tests carried out on human remains have always yielded useful results. Apart from isotope analyses, other scientifically advanced tests can identify biomolecules like calcium, strontium, and phosphorus which offers indication on health.

There are tests that measure and define antibodies, antigens, and DNA of ancient individuals.

This method is not without its drawbacks; human remains is easily contaminated especially with flora and fauna from their surroundings, human handling in the field or laboratory also poses a problem. Furthermore, it can be quite expensive sometimes.

HUMAN GENOME SEQUENCING

A human genome is a set of biochemical instructions that are required to develop an individual right from a single-celled embryonic state, these instructions define the molecules and dictates the interactions required to build up and maintain the individual, and it is passed on from generation to generation through reproduction.

The major part of this instruction is found in the molecules of the deoxyribonucleic acid (DNA) the individual inherits. The primary way information is encoded in the DNA molecules is from the order of the four constituent

Cost Of Human DNA Sequencing From 2001-2017

deoxyribonucleotides; Adenine, Guanine, Thymine, and Cytosine which are present in each DNA molecule. Therefore sequencing a genome means finding out the order by which the nucleotides are present in an individual.

J. Craig Venter, a genomics entrepreneur, was the first person to have his genome completely sequenced, which took about 11 years and gulped a whopping hundred million dollars. It was published in 2001.

In 2007 DNA pioneer James Watson’s genome was also fully sequenced using modern technological advancements which took just four months and about $1.5 million dollars to accomplish the sequencing of about 6 billion pairs of his DNA. This was made possible by the use of next-generation rapid sequencing machines which allows many sequencing reactions to proceed at the same time and the same surface. There have been rapid improvements since then, and today a complete human genome sequencing costs about $1000 or less.

SOURCES

  • Meredith Wadman. James Watson’s Genome Sequenced at High Speed. Published online by www.nature.com on 16th April 2008. https://www.nature.com/news/2008/080416/full/452788b.html
  • Neil. H. Metcalfe. In What Ways Can Human Skeletal Remains Be Used To Understand Health And disease From The Past. April, 2007. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2600025/#ref3

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