Aboriginal Australians represent one of the oldest continuous cultures outside Africa, with evidence indicating that their ancestors arrived in the ancient landmass of Sahul (present-day New Guinea and Australia) ~55 thousand years ago. Genetic studies, though limited, have demonstrated both the uniqueness and antiquity of Aboriginal Australian genomes. We have further resolved known Aboriginal Australian mitochondrial haplogroups and discovered novel indigenous lineages by sequencing the mitogenomes of 127 contemporary Aboriginal Australians. In particular, the more common haplogroups observed in our dataset included M42a, M42c, S, P5 and P12, followed by rarer haplogroups M15, M16, N13, O, P3, P6 and P8. We propose some major phylogenetic rearrangements, such as in haplogroup P where we delinked P4a and P4b and redefined them as P4 (New Guinean) and P11 (Australian), respectively. Haplogroup P2b was identified as a novel clade potentially restricted to Torres Strait Islanders. Nearly all Aboriginal Australian mitochondrial haplogroups detected appear to be ancient, with no evidence of later introgression during the Holocene. Our findings greatly increase knowledge about the geographic distribution and phylogenetic structure of mitochondrial lineages that have survived in contemporary descendants of Australia’s first settlers.
Histomorphometric analysis of human cortical bone has documented the occurrence of secondary osteon variants. These include drifting osteons which form tails as they move erratically through the cortex and Type II osteons which show partial resorption and redeposition within the cement line of the osteon. Little is known about the biological significance of these variants. Prior studies suggested correlations with age, biomechanics, diet, and mineral homeostasis. No study has yet tested for osteon variant associations with static measures of bone remodeling. In this study, thin sections (n = 112) of the posterior femur representing a late English Medieval adult human osteological collection, subdivided by age, sex, and socio-economic status, were examined to determine whether remodeling indicators reconstructed from osteon parameters (area, diameter, area ratios) and densities differed between categories of presence or absence of Type II and drifting osteon variants. Of the 112 sections, 33 presented with Type II osteons, and 38 had drifting osteons. Sporadic statistically significant results were identified. Haversian canal:osteon area ratio differed (p = 0.017) with Type II osteon presence, Type II osteons were more prevalent in males than females (p = 0.048), and drifting osteons were associated with smaller osteon (p = 0.049) and Haversian canal area (p = 0.05).These results may be explained through some biological (sex) and social (status) processes such as a period of physiological recovery (e.g., following lactation, malnutrition). However, the general lack of consistent relationships between osteon variants and remodeling indicators suggests they occur as a result of natural variation.
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Bone is dynamic, undergoing metabolic changes in response to behavioral and pathological stimuli. This information can be reconstructed in bioarchaeology using histological methods, providing another avenue to explore the experiences of past peoples. We report histological findings from midshaft femoral cortical bone of an identified individual from nineteenth-century New Zealand, who suffered from tuberculosis and had a historically documented period of invalidism. Materials: Burial 21 (B21) is a middle-aged male excavated from the nineteenth-century site of St. John’s burial ground, Milton. B21’s left proximal femur and acetabulum exhibited lytic lesions associated with tuberculosis-induced destruction of bone. Documentation, including a cause of death of “pneumonic phthisis haemorrhage,” and various biographic details exist for this burial. These suggest that B21’s left and right midshaft femur were under asymmetric biomechanical and pathological conditions and should show differences in the underlying bone remodeling. Methods: We collected data on Haversian bone microstructure geometric properties and densities from a total of 148 secondary osteons and 481 Haversian canals. Results: The left femur, from the tuberculosis-inflicted hip joint, had fewer, larger, and more irregularly shaped canals and osteons than the right femur. Discussion and Conclusion: These findings may indicate the left femur received less biomechanical stimulation than the right femur due to decreased weightbearing. It is also possible that the tuberculosis infection in this individual impacted his bone metabolic activity, leading to increased experiences of bone loss. The presented histological approach may enhance interpretations in bioarchaeology by identifying whether bone remodeling changes occur as a result of long-or short-term disuse.
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