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Forensic Anthropology & Taphonomy

A serious issue faced in South Africa is the resolution of crime, one matter arising being the identification of deceased individuals. South Africa has a high number of missing and murdered people, with 21 022 murder cases reported across South Africa from April 2018 to March 2019 (SAPS, 2019). The City of Cape Town Metropole alone had 3157 murders reported in 2019 (SAPS, 2019). The challenges faced in identifying these remains are not only attributed to excessive caseloads, but also due to high volumes of decomposed, burnt, and skeletonised remains entering mortuaries, often lacking formal identification. With Forensic Anthropology Cape Town (FACT) at the University of Cape Town we apply our knowledge to assist the South African Police and Forensic Pathology Services with identification of decomposed and burnt remains. My research focuses primarily on methods of identifying human remains and forensic taphonomic studies.

Identification

In addition to social and criminal justice, identifying the dead allows closure and understanding for the living, and is considered an important aspect of population health. For these reasons, there is a global drive to improve methods of forensic identification internationally. Locally significant research analysing FACT casework has been conducted to discern the extent that unidentified persons are an issue in the Cape; identify populations most at risk of being unidentified; the locations where most unidentified bodies were recovered; identify and determine the applicability of the methods routinely employed in estimating demographic profiles of the local population (FSIR 1: 100042, 2019). This research is useful for the development of intervention strategies to reduce the number of unidentified bodies and research focused on building demographic standards for southern African populations and specifically targeting ones that work well in the Cape. Considering the diverse genetic, cultural and ancestral composition of the population, there is pertinent need to establish innovative and novel techniques to assist in identification. Biological parameters (age, ancestry, sex and stature) are assessed to assist with identification although age, stature and sex estimation are sensitive to ancestry. Therefore, forensic anthropologists ensure that these standard methods and techniques are reliable and relevant. Novel techniques within the field of biological anthropology enable quantification of morphology. This has included investigating the use of the geometric morphometric properties of the zygoma for estimating ancestry in a Cape Town population (Sci & Just 60: 284-292, 2020).

In addition to developing demographic standards, my research has explored the use of DNA in identifying the dead. Currently, DNA is the golden standard in confirming identity and therefore is often done concurrently with forensic anthropological investigation. For my PhD, undertaken at the University of Witwatersrand, I combined these two ideas and developed novel molecular sex determination methods optimal for human forensic and archaeological skeletal remains. As destructive sampling should be avoided when dealing with human remains in genetic studies, I developed a new minimally invasive bone extraction method (Am J Phys Anthropol 139: 596-599, 2009). Additionally, I developed two novel systems of molecular sex identification suitable for skeletal material using the Amelogenin gene (Forensic Sci Int: Gene 3: 74-79, 2009). Subsequently, this method was implemented on the remains of Chinese indentured laborers in South Africa (S Afr J Sci 106: 65-68, 2010). Further to this work, in collaboration with a marine forensic taphonomic research project and Dr. Heathfield in the Division of Forensic Medicine (UCT), we investigated optimisation of DNA extraction methods for samples exposed to seawater; and examined DNA degradation in this environment (Forensic Sci Int Genet Suppl Ser 7 (1): 580-581, 2019). The oceanic environment is particularly under-researched world-wide within the field of forensics, and in Cape Town, there are numerous marine wash-up cases annually which are challenging to identify. Therefore, research in this field is important and Dr. Heathfield and I continue to work together to better understand DNA preservation in this environment and improve methods of DNA extraction for samples exposed to seawater.

Forensic Taphonomy

Taphonomy (derived from the Greek for “burial law”) was coined in 1940 by Efremov who defined it as, “…the study of the transition of animal remains from the biosphere to the lithosphere.” In essence, it is the study of the preservation of biological material over long periods of time. Accordingly, it has found a natural home in the fields of archaeology, palaeontology, and biological anthropology. The principles of taphonomy may, however, be applied to shorter timescales, typically in forensic cases (<50 years). Here, the goal is understanding the decomposition process of the remains in question to help inform reconstruction of the circumstances surrounding death and estimate the time-since-death (AKA: the post-mortem interval, or PMI). To obtain such an understanding, forensic taphonomists have been studying the decomposition of both animal and human remains since the late 1950s. This has provided insight into the varied roles for a diverse array of decomposers and the environmental variables which affect them. One of the key discoveries has been the environmental specificity of decomposition. This has triggered a global research enterprise for establishing biogeographically specific data on decomposition, especially in countries where the need is greatest.

With more than 20,000 murders per year, South Africa is one of those countries, and Cape Town is the epicentre, contributing one fifth of the national total, ~9% of whom go unidentified every year. Being able to determine the PMI may improve the chances of successfully identifying these victims of crime and tragic circumstances. Towards achieving this, between 2014 and 2016, Dr Devin Finaughty established the first baseline data on terrestrial decomposition in two of the most forensically significant habitats in Cape Town for his PhD under the supervision of Professor Emeritus Alan Morris – laying the foundations for understanding terrestrial decomposition in Cape Town’s globally unique biome. Among the novel discoveries were evidence of a previously unknown mechanism for precocious natural mummification in temperate climates, identification of extensive scavenging by Cape grey mongoose, and seasonal succession patterns of forensically significant insects in the Western Cape.

Professor Morris also co-supervised the sister project to Dr Finaughty’s which ran in tandem: Belinda Speed’s marine decomposition study in False Bay. This multi-year in-situ study has not only established world-first data on shallow-water marine decay but contributed important knowledge for helping Cape Town’s forensic practitioners investigate and resolve the many forensic cases which wash up on the City’s shores each year.

Both projects have spawned new research streams which have grown considerably in scope and influence under the guidance of Associate Professor Victoria Gibbon. On the terrestrial side in collaboration with Dr. Finaughty (Kent University), great strides have been made in characterising the scavenger role of the Cape grey mongoose and determining the magnitude of their influence on the decomposition process. PhD student, Max Spies, has played an integral part in this research stream, and it is set to grow further as part of a national collaboration with UNISA-based ecologist and camera trap expert, Dr Trevor McIntyre. Max remains a member of the research group and is presently investigating the effect of clothing and environmental carrion biomass load on decomposition in Cape Town. As a long-term tandem project, the time interval for osteological bleaching and degradation of clothing is also being investigated. Finally, together with Dr Finaughty – now based in the UK – the research group is developing full automation of taphonomic data recording – a world-leading research enterprise.

PUBLICATIONS:

  • Finaughty D, Spies M, Pead J, Gibbon VE. 2020. Automation: A golden ticket for taphonomic research? Forensic Science International. https://doi.org/10.1016/j.forsciint.2020.110276
  • Spies MJ, Finaughty DA, Friedling LJ, Gibbon VE. 2020. The effect of clothing on decomposition and vertebrate scavengers in cooler months of the temperate southwestern Cape, South Africa. Forensic Science International 309:110197. https://doi.org/10.1016/j.forsciint.2020.110197
  • Tawha T, Dinkele E, Mole C, Gibbon VE. 2020. Assessing zygomatic shape and size for estimating sex and ancestry in a South African sample. Science & Justice 60: 284-292. https://doi.org/10.1016/j.scijus.2020.01.003
  • Dinkele ES, Ballo R, Fredlund V, Ramesar R, Gibbon V. 2020. Mseleni joint disease: an endemic arthritis of unknown cause. The Lancet Rheumatology 2(1): e8-e9. https://doi.org/10.1016/S2665-9913(19)30104-3
  • Baliso A, Finaughty C, Gibbon VE. 2019. Identification of the deceased: use of forensic anthropology at Cape Town's busiest medico-legal laboratory. Forensic Science International: Reports 1:100042. https://doi.org/10.1016/j.fsir.2019.100042
  • Finaughty C, Gibbon VE, Speed B, Heathfield L. 2019. A pilot study investigating DNA recovery from teeth in a South African natural marine environment. Forensic Science International: Genetics Supplement Series https://doi.org/10.1016/j.fsigss.2019.10.097
  • Finaughty D, Morris AG. 2019. Precocious natural mummification in a temperate climate (Western Cape, South Africa). Forensic Science International 303:109948. https://doi.org/10.1016/j.forsciint.2019.109948
  • Mazengenya P, Mokoena P, Billings BK, Bidmos M, Gibbon VE. 2019. Development of discriminant functions to estimate sex in upper limb bones for mixed ancestry South Africans. Science and Justice 59(6): 660-666. https://doi.org/10.1016/j.scijus.2019.06.007
  • Forbes MNS, Finaughty DA, Miles KL, Gibbon VE. 2019. Inaccuracy of accumulated degree day models for estimating terrestrial post-mortem intervals in Cape Town, South Africa. Forensic Science International 296: 67-73 (rank 5/16; impact factor 2.271; citations: GS:0; WOS:0; S:0). https://doi.org/10.1016/j.forsciint.2019.01.008
  • Spies M, Gibbon VE, Finaughty D. 2018. Forensic taphonomy: Vertebrate scavenging in the temperate southwestern Cape, South Africa. Forensic Science International 290: 62-69 (rank 5/16; impact factor 2.271; citations: GS:1; WOS:0; S:1). https://doi.org/10.1016/j.forsciint.2018.06.022
  • Spies M, Finaughty D, Gibbon VE. 2018. Forensic taphonomy: Scavenger-induced scattering patterns in the temperate southwestern Cape, South Africa. Forensic Science International . DOI: 10.1016/j.forsciint.2018.06.015