Towards a biological profile for South African perinatal remains : osteological and genetic perspectives

Forensic identification of abandoned and suspected infanticide cases admitted to the South African Forensic Pathology Services is often impossible due to decomposition of the remains. In these cases, investigation of suspected criminal activity is almost never pursued. Ancillary tests in the form of anthropological and molecular analyses can assist with the forensic identification of perinatal remains. To provide fundamental information about bone development of perinatal skeleton, osteological and genetic techniques focusing on the pars basilaris, pars lateralis, sternal rib and left femur were used. Samples were obtained from unidentified and unclaimed remains originating from the Johannesburg Forensic Pathology Service (JFPS). To provide a biological age to individuals in the collection, dental aging was used to categorize remains for comparisons with anthropological and molecular data. A molecular protocol was designed to sex individuals using the X-linked G6PD and Y-linked SRY genes. Bone development was studied using osteometric and morphological data of dry bone remains coupled with bone mineral density analysis (Micro-CT). The methylation levels of CpG rich sites within the promoter region of selected bone-associated genes were incorporated to examine silencing of genes during development. Osteological results support the use of the pars basilaris, pars lateralis and femur for age-at-death estimations as well as provide the foundation for dry bone aging criteria for South African individuals. Data compared with established skeletal aging standards indicated developmental differences between populations. Through the use of animal models and the perinatal sternal rib tissue, insights and precautions into the use of post mortem bone derived RNA for forensic applications is communicated. The methylation status of CpG rich sites within the promoter regions support the hypothesis for interdependent machinery involving selected genes during early bone development.

The Ages-at-Death and Sexes of the Sunghir Humans

Assessment of the ages-at-death and the probable sexes of the Sunghir humans provides a baseline for their paleobiological evaluation. The former is particularly important for the comparative analysis of the immature Sunghir 2 and 3 skeletons, given the marked changes in size and shape with development. The latter is more important for the adult Sunghir 1, 5, and 6 remains, given some degree of sexual dimorphism among recent humans and apparently within Late Pleistocene early modern humans. In the assessment of age-at-death, it is necessary to evaluate the remains with reference to chronological scales derived from extant human populations of known age (or very recent historical skeletal samples with documented ages). This consideration applies particularly to changes in fibrocartilaginous articulations with age (in this case, a sternal rib end and an auricular surface of Sunghir 1) and to dental calcification during development (for Sunghir 2 and 3). The majority of the data available for these approaches derives from recent European and European-derived (primarily North American) populations, with occasional cross-references to more limited data on recent populations from elsewhere in the Old World. The one exception to this requirement is dental occlusal attrition, for which very general Late Pleistocene (and preindustrial Holocene) reference samples are appropriate, in all cases using scales that are based either on other methods of skeletal aging or employ some version of the “Miles technique” (sequential assessment of dental wear for postcanine teeth as they come into functional occlusion; Brothwell 1981). The determination of sex is most reliable when it utilizes the pelvis, and there is a series of criteria for pelvic sexual evaluation that appear to be universal among recent humans (Brůžek 2002). These dimorphic features mostly appear during adolescence associated with differential lateral development of the pelvis (Coleman 1969; Lavelle 1995). Dimorphic aspects of the greater sciatic notch may appear prior to puberty (Holcomb and Konigsberg 1995; Scheuer and Black 2000), but tests sexing recent human immature skeletons of known sex have provided poor results and tend to identify males more accurately than females (Cardoso and Saunders 2008; Vlak et al. 2008; Wilson et al. 2008).

Reliability of the individual age assessment at the time of death based on sternal rib-ends' morphology in Balkan population

This paper analyzes the reliability of the I?can?s sternal rib-ends phase method for the assessment of individual age at the time of death in the Balkan population. The method is based on the morphological age changes of the sternal rib ends. The tested samples consisted of 65 ribs from autopsy cases in the Institute for Forensic Medicine, University of Belgrade, during 1999-2002 (23 females, and 42 males of various ages, ranged from 17-91 years), according to the forensic documents. Significant differences between the real chronological age of the individuals and the values established by the I?can?s method was found, especially in the older categories (phases 6 and 7), in both males and females. The results of the discriminative analysis showed the values of the highest diagnostic relevance for the assessment of age in our population: the change of the depth of the articular fossa, the thickness of its walls, and the quality of the bones.