Effect of different healing stages on stable isotope ratios in skeletal lesions.

INTRODUCTION: Physiological stress is one of the various factors that can have an impact on stable isotope ratios. However, its effect on bone collagen stable isotope ratios is still not fully understood. This study aims to build on previous research on how different disease stages may affect bone collagen stable isotope ratios. MATERIALS AND METHODS: Carbon (δ13 C) and nitrogen (δ15 N) isotope ratios were assessed in 33 skeletons that retained evidence of infectious disease and healed fractures. Samples were taken from active lesions (long bones n = 14; ribs n = 4), healed lesions (long bones n = 10; ribs n = 9), or a fracture callus (long bones n = 9; ribs n = 3). Results were compared to stable isotope ratios calculated for regions on these bones that did not retain evidence of disease or fracture. RESULTS: Long bones with active lesions had a significantly higher average δ15 N (δ15 N = 11.1 ± 0.9‰) compared to those without lesions (δ15 N = 10.7 ± 0.7‰; p = .02), while fracture calluses showed the largest range for both δ15 N and δ13 C. There were no significant differences in stable isotope ratios when compared between nonlesion and lesion sites in the ribs. DISCUSSION: The increase in δ15 N seen in active lesions, when compared with δ15 N from nonlesion regions on the same long bone, may be a consequence of altered protein metabolism. The high variability of δ15 N and δ13 C in fractures may be related to different healing stages of the calluses. This study suggests that stable isotope data can contribute information about diseases in the past, as well as an individual's response to diseases in the absence of modern medicine and antibiotics.

Shrouded in history: Unveiling the ways of life of an early Muslim population in Santarém, Portugal (8th- 10th century AD).

In around 716 AD, the city of Santarém, Portugal, was conquered by the Berber and Arab armies that swept the Iberian Peninsula and went on to rule the region until the 12th century. Archaeological excavations in 2007/08 discovered an Islamic necropolis (Avenida 5 de Outubro #2-8) that appears to contain the remains of an early Muslim population in Santarém (8th- 10th century). In this study, skeletal material from 58 adult individuals was analysed for stable carbon (δ13Ccol; δ13Cap), nitrogen (δ15N) and sulphur (δ34S) isotope ratios in bones, and stable oxygen (δ18O), carbon (δ13Cen) and radiogenic strontium (87Sr/86Sr) isotopes in tooth enamel. The results of this study revealed a dietary pattern of predominantly C3-plant and domestic C3-fed herbivore consumption during adulthood (δ13Ccol and δ15N, respectively) but a higher proportion of C4-plant input during childhood (δ13Cen) for some individuals-interpreted as possible childhood consumption of millet porridge, a common practice in North Africa-in those with unorthodox burial types (Groups 1 and 2) that was not practiced in the individuals with canonical burials (Group 3). In this first mobility study of a medieval Muslim population in Portugal, δ18ODW values revealed greater heterogeneity in Groups 1 and 2, consistent with diverse origins, some in more humid regions than Santarém when compared to regional precipitation δ18O data, contrasting the more homogenous Group 3, consistent with the local precipitation δ18O range. Ancient DNA analysis conducted on three individuals revealed maternal (mtDNA) and paternal (Y-chromosome) lineages compatible with a North African origin for (at least) some of the individuals. Additionally, mobility of females in this population was higher than males, potentially resulting from a patrilocal social system, practiced in Berber and Arab communities. These results serve to offer a more detailed insight into the ancestry and cultural practices of early Muslim populations in Iberia.

Lombards on the move--an integrative study of the migration period cemetery at Szólád, Hungary.

In 2005 to 2007 45 skeletons of adults and subadults were excavated at the Lombard period cemetery at Szólád (6th century A.D.), Hungary. Embedded into the well-recorded historical context, the article presents the results obtained by an integrative investigation including anthropological, molecular genetic and isotopic (δ(15)N, δ(13)C, (87)Sr/(86)Sr) analyses. Skeletal stress markers as well as traces of interpersonal violence were found to occur frequently. The mitochondrial DNA profiles revealed a heterogeneous spectrum of lineages that belong to the haplogroups H, U, J, HV, T2, I, and K, which are common in present-day Europe and in the Near East, while N1a and N1b are today quite rare. Evidence of possible direct maternal kinship was identified in only three pairs of individuals. According to enamel strontium isotope ratios, at least 31% of the individuals died at a location other than their birthplace and/or had moved during childhood. Based on the peculiar 87 Sr/86 Sr ratio distribution between females, males, and subadults in comparison to local vegetation and soil samples, we propose a three-phase model of group movement. An initial patrilocal group with narrower male but wider female Sr isotope distribution settled at Szólád, whilst the majority of subadults represented in the cemetery yielded a distinct Sr isotope signature. Owing to the virtual absence of Szólád-born adults in the cemetery, we may conclude that the settlement was abandoned after approx. one generation. Population heterogeneity is furthermore supported by the carbon and nitrogen isotope data. They indicate that a group of high-ranking men had access to larger shares of animal-derived food whilst a few individuals consumed remarkable amounts of millet. The inferred dynamics of the burial community are in agreement with hypotheses of a highly mobile lifestyle during the Migration Period and a short-term occupation of Pannonia by Lombard settlers as conveyed by written sources.

Bioavailable 87Sr/86Sr in different environmental samples--effects of anthropogenic contamination and implications for isoscapes in past migration studies.

(87)Sr/(86)Sr reference maps (isoscapes) are a key tool for investigating past human and animal migrations. However, there is little understanding of which biosphere samples are best proxies for local bioavailable Sr when dealing with movements of past populations. In this study, biological and geological samples (ground vegetation, tree leaves, rock leachates, water, soil extracts, as well as modern and archeological animal teeth and snail shells) were collected in the vicinity of two early medieval cemeteries ("Thuringians", 5-6th century AD) in central Germany, in order to characterize (87)Sr/(86)Sr of the local biosphere. Animal tooth enamel is not appropriate in this specific context to provide a reliable (87)Sr/(86)Sr baseline for investigating past human migration. Archeological faunal teeth data (pig, sheep/goat, and cattle) indicates a different feeding area compared to that of the human population and modern deer teeth (87)Sr/(86)Sr suggest the influence of chemical fertilizers. Soil leachates do not yield consistent (87)Sr/(86)Sr, and (87)Sr/(86)Sr of snail shells are biased towards values for soil carbonates. In contrast, water and vegetation samples seem to provide the most accurate estimates of bioavailable (87)Sr/(86)Sr to generate Sr isoscapes in the study area. Long-term environmental archives of bioavailable (87)Sr/(86)Sr such as freshwater bivalve shells and tree cores were examined in order to track potential historic anthropogenic contamination of the water and the vegetation. The data obtained from the archeological bivalve shells show that the modern rivers yield (87)Sr/(86)Sr ratios which are similar to those of the past. However, the tree cores registered decreasing (87)Sr/(86)Sr values over time towards present day likely mirroring anthropogenic activities such as forest liming, coal mining and/or soil acidification. The comparison of (87)Sr/(86)Sr of the Thuringian skeletons excavated in the same area also shows that the vegetation samples are very likely anthropogenically influenced to some extent, affecting especially (87)Sr/(86)Sr of the shallow rooted plants.